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Recent repairs

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Dillen
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Dillen Posted: Wed, Mar 13 2013 3:55 PM

In this thread, I will try to give a few brief writeups of recent repairs I've had on the bench, heavily inspired
by the notebook area of Tims great website that I very much enjoy reading myself.
Feel free to comment.

Martin

Dillen
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Dillen replied on Wed, Mar 13 2013 3:55 PM

Beovox 1200 (type 6227)
From Helsingoer/Denmark
Owner has a complete Beosystem 1200 in beautiful oak, Beomaster, Beogram, Beovox.
One speaker had an intermittent tweeter. It got worse and worse and he decided to bring it to me.
A quick check confirmed that the tweeter itself was fine but it would only reproduce sound when the
cabinet was held face down.
A check of the filter board revealed that one of the two capacitors were only soldered properly at one end, the
other end pulled right up from the solder joint.
After more than 40 years on duty the old capacitors were retired and two fresh capacitors were fitted, the filter
board in the other cabinet had the same treatment to keep them identical and they both played on nicely again.
What a nice system this is.
Actually, the Beovox 1200 was produced in no less than three versions, both two-way and three-way versions exists
and to add to the confusion type 6227 can be either...
These were type 6227 in the two-way versions.

Martin

Dillen
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Dillen replied on Wed, Mar 13 2013 3:56 PM

Beocord 2400 cassettedeck.
Based in Copenhagen, the owner brought this one in for repairs himself.
A nice and rather rare white design version and a very beautiful one at that but the deck showed no signs of life.
The mains fuse had blown. This usually happens for a reason and in this case the culprit was capacitor C20,
a 2200uF axial component in the power supply. It had turned into a dead short.
A nice blue replacement cured the poor thing. A nearby capacitor of the same brand, type and value
was replaced too for good measure.
Technically perhaps not the best deck in the history of recorded music but certainly not the worst either.
These decks are slowly but certainly getting rare. Worth holding on to.

Martin

Dillen
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Dillen replied on Wed, Mar 13 2013 3:56 PM

A Beomaster 700K from my own collection.
At power up on the variac it was dead silent but pulling a little current.
The dial lamps were both burned. Two new lamps were mounted but that alone did not restore dial lighting.
The dial lamps have a dedicated fuse and fuse holder and both were completely green with oxidation.
New parts allowed the dial to be relit.
This always gives a good indication whether the radio chassis is powered or not.
A Beovox 1702 was connected as external speaker. It played something but sounded distorted.
FM stations were few and weak. Of AM stations there were none.
No reaction on the S-meter was noticed either.
The internal speaker leads was measured, leads were fine but the speaker was found o/c.
That is, measuring the speakers voice coil, across the thin leads running on the outside of the cone, the coil itself

measured fine.
The problem was narrowed down to a broken flex wire from the solder tag to the cone. It was soldered back in
place and the joint reinforced with a tiny drop of contact glue.
This brought back sound but didn't remove the distortion and the volume was still very low.
Sensitivity problems in the Beomaster 700K is often caused by the dreadful AF transistors used for the IF stages.
This case was no different. Two new IF transistors were fitted and I was rewarded with a dial now filled with stations
on all wavebands and volume was up to par as well.
Even a few stations could be found on shortwave which is almost always very quiet in my neck of the woods.
The S-meter was also back to being busy as the dial was travelled.
Four new rubber feet and a dose of teak oil ended this restoration.

Martin

Dillen
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Dillen replied on Wed, Mar 13 2013 3:59 PM

Sony PS-T1 record player from a work colleagues daughter.
Speed had jitter, easily visible on the built-in strobo light. You could actually see that it was badly wrong by just
looking at the platter.
Looked like it was trying to switch between 33 and 45 twice for every revolution. Possible only because the platter was
very thin and lightweight.
Needless to put a record on this one at this point.
It even attempted to start backwards occasionally.
It's a very simple build.
The direct drive brushless motor was taken apart, all 4 coils measured fine which is good since they
look dreadfully machine specific and I have no Sony parts in the dungeons.
Driver transistors all measured fine but the signal fed to them looked very different on the scope.
The culprit was a simple little 8-pin IC 4558 where one of its dual opamps had given up the ghost.
This type of IC is also used in some B&O machines so the component drawer could provide a new IC which saw
it running fine, entertaining me for the rest of the evening.
I rarely do repairs beside B&O audio stuff but I thought I'd put it here since it was actually a recent repair and
it could come in handy for the odd surfer in need.
It was connected to a Beomaster 901 that has been soak testing for some days in an attempt to reproduce an
intermittent failure that I never experienced but the owner claims it has.
Ten days now without a single burp but that's a different story.

Martin

Dillen
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Dillen replied on Wed, Mar 13 2013 4:00 PM

Beocord 8004 HX-PRO
This one arrived from the UK.
The owner claimed it had gone silent and the VU-meters no longer showed anything.
In an attempt to find the reason for this fault, the owner pulled some plugs and connectors around the
mechanical tapedeck section and put them back. This, however, merely resulted in a completely dead Beocord.
It arrived here in its original box, a very nice touch.
A couple of quick voltage samples showed that there were no connection to the regulators at the cooling fin.
This was caused by one of the ribbon cables not being fully inserted into its socket. They are kinda flimsy so this
was not a first.
Now, with power available again, the deck could be further examined.
The deck was silent alright, and on both channels so some common component was to be suspected.
All the major voltages were fine but the 7V reference voltage used for the Dolby ICs was missing.
A shorted 220uF capacitor of the dreadful black Roederstein type was duly replaced which restored sound and
VU meter action.
The record/playback relay was the original non-airtight type. I've seen this relay cause problems too often and
I like to replace it with an airtight type. It's a fairly cheap component and a 5-minute job so I replace it in
every Beocord on the bench.
A quick head clean, a good testing and it was returned to the owner.

Martin

j0hnbarker
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I was going to comment that this is a nice feature Martin, then I saw that one of the items was mine!

Excellent stuff and please keep posting :)

John

beotoss
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beotoss replied on Wed, Mar 13 2013 4:38 PM

Keep going!......

Friedmett
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Friedmett replied on Wed, Mar 13 2013 4:38 PM

Great Idea Dillen!

I have been kind of wanting this for some time from you.

As you have my newly bought white Beosystem 6500 currently on the bench feel free to post any writeups or pictures you can. This goes for all B&O that you get from me.

 

Dillen
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Dillen replied on Thu, Mar 14 2013 4:42 PM

Beolab Penta mk III
This pair was delivered to my door by the owner.
Very beautiful speakers that were both still playing but the owner was of the opinion that they were
no longer performing their best and he wanted me to restore them to their former glory.
A brief test proved one of them to actually sound somewhat alright while the other had a strange
midrange reproduction as if one or more of the midrange drivers had foam rot but I was told that they were
already refoam'ed so that couldn't be the case.
Work started and the crossover filters received new capacitors. So did the amplifier section and
the two large cans in the power supply in each tower was replaced with new 105degC types.
The signal path was upgraded with a couple of WIMA MKS-2 capacitors and the wonderful OPA2134 operational amplifier.
A check revealed the usual cracked solder joints to the driver transistors and the ribbon cable to the fold out front panel.
The midrange problem turned out to be caused by a bad refoam job; One driver rubbed badly on the center piece
when moved and all four had surrounds fitted that were cut down to size, presumably because the refoamer didn't
have the correct size at hand. Where the cut ends met up, there was just an opening, no glue or anything.
The glue used didn't hold on particularly good so the surrounds could be pulled right off.
When removed the original size of the foam ring could immediately be revealed in that the remains sprung
back to the size of what could easily have been a 5" ring. And this was a pro job ( ! ? ).
All internal cabling in the towers was then bypassed and new Van Del Hul Snowline cable was fitted.
All the spade-type plugs were cut off and the connections soldered instead. Let me say right away that it's
my opinion that those spade-type connectors are in fact very good and the original internal cabling adequate but
the owner wanted it this way and, well, it doesn't harm anything as long as cable lengths are kept long enough for
the crossover boards to be pulled out without desoldering anything.
New trimmers were fitted to the amplifiers and the idle current and DC offsets were set as per factory specs.
Three days of work and the final testing proved the job to be worthwhile.
The speakers now sounded considerably more fresh, open and ready and also much more identical. Gone
was also the strange midrange performance.
The restoration was rounded off with a fitting of fresh cloth to the four front grill panels. The original cloth was
actually still intact but it had faded and greyed badly as most of these have by now.
Everything now sounded clear, bright and undisturbed again and the speakers looked great.
The Pentas were always one of my own favourite speaker designs.

Martin

Dillen
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Dillen replied on Thu, Mar 14 2013 4:42 PM

Beomaster 2400-2
The owner brought this white finish version in for repairs to the balance potentiometer and fitting of new lamps.
He had tried to get to the lamps himself but eventually gave up and ended up with a Beomaster that would
no longer go into standby when activating the sensitouch pad.
A full set of fresh lamps were fitted and the most fault-prone capacitors were attended as well.
The balance potentiometer was then repaired and the treble and bass ones checked, the last two
were both of the later replacement types so fine.
It's not a very easy product to assemble correctly again after servicing and this was exactly where the
owner had failed with regards to the standby fault. Correct assembly, soak testing and the Beomaster was then
handed over to the owner at the local train station.

Martin

Dillen
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Dillen replied on Sat, Mar 16 2013 7:28 AM

Beogram CD3500 from Sweden.
The owner said it wouldn't play.
Sure enough it wouldn't. It made a slight, kinda nervous, jitter to the disc and went into standby after a few seconds.
Repeated attempts caused a small puff of grey smoke to emit from the rear grill.
Surely, this was not the usual "C2103 failure".
The smoke was coming from one of the 10 ohms resistors in the spindle motor drive circuit.
I remember that the service manual has a serious typo in this circuit, where transistors polarity (types) has been
wrongly indicated.
Sure enough, with the servo board out and flipped over, it was obvious that someone did some soldering around this
circuit previously and, not surprisingly, had a wrong type of transistor fitted.
The motor is a simple DC type. It measured fine and ran without a problem fed directly from one of my workbench B&O SN14 powersupplies.
Two new transistors and two new resistors had the CD spinning nicely and smokefree again and with a bunch of
new capacitors in the servo board it would now also reproduce sound again.
Glass panel fastened and it was returned to the owner.

Beovox CX50.
Two woofers arrived from Jutland for refoaming.
One woofer had a nasty fold to the cone so a replacement woofer was found.

Martin

Dillen
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Dillen replied on Sun, Mar 17 2013 6:36 AM

Beovox 2702.
Two woofers and a pair of crossover filterboards arrived from Germany for refoaming and recap'ing.
One woofer had a damaged coil with the innermost windings unwound and lose. Fortunately the dungeons
could provide an original Peerless replacement.

Dirigent 609K.
Arrived from Belgium.
Owner claimed one channel was very quiet, almost silent. Distorted at best.
Arriving here, the thing was completely silent.
Easy diagnose as the paxolin valve sockets on the output stage board had disintegrated and one valve only
barely held on.
This is a common fault in these wonderful receivers.
A fresh pair of valve sockets of a ceramic type was fitted. They will deal with the heat from the valves much better and last practically forever. The original sockets only lasted 50 years - talk about a design flaw... :-)
A small bunch of electrolytic capacitors were replaced on the same board - they live a hard and warm life near the output valves and the poor thing was then back up and running, connected to the workshop Beovox 1702s it played for several hours with no further problems.
I'm always impressed with the sound of valves.

Martin

Rich
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Rich replied on Sun, Mar 17 2013 2:59 PM
I hate it when products only last 50 years. ;-)

Great thread as always, Martin.

Blah blah blah, blah blah ba ran

Beobuddy
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Beobuddy replied on Sun, Mar 17 2013 5:50 PM

Recent repairs/overhauls during last year (14-15 months)...

Beolab Penta's (4x) -complete overhaul, recap, upgrade filters and amplifier,  cloth, trimmers etc.
Beomaster 7000 (2) -complete overhaul, recap, trimmers, etc
Beomaster 6500  (2x) -complete overhaul, recap, trimmers, relais, etc
Beomaster 5500  (3x) -complete overhaul, recap, trimmers, relais, etc
Beomaster 8000 (2x) -repair, partitional recap, trimmer
Beomaster 4000 (2x) -repair, mostly recap and defective main switches
Beomaster 4400 (2x) -repair and overhaul. Also defective mainswith, caps, trimmers, etc.
Beomaster 2400-2 (2x) -overhaul, partional recap, trimmers, etc
Beomaster 1900 (1x) -overhaul, new caps
Beomaster 1001 (1x) -complete overhaul/restauration
Beomaster 900K (3x) -complete overhaul/restauration
Beocord 5500 (2x) -some new caps and belts
Beogram CD5500/6500(4x) -some new caps, belts and thoroughly cleaning
Beogram CDX (1x) -repair hinge
Beogram 7000 (1x) -repair, thoroughly cleaning, new grease
Beogram 5500 (2x) -repair, thorougly cleaning, new grease.
Beogram 4002 (1x) -repair, new belts, grease, etc.
Beocenter 4600 (1x) -complete restauration/overhaul. New cap, belts, etc.
Beosound 9000 (2x) -repair, overhaul, new belts, caps, laser units etc. (6 discs version)
Beosound 3000 (1x) -repair, new laser
Beocenter 2300  (2x) -repair, new laser
Beosound 3 (2x) -repair, new topplate
Beovision 8 (1x) -new screen
Beovision 7 (1x) -repair
Beovision MX7000 (2x) -repair

Probably more, but can't remember, so probably longer ago than 1 year...

For 4 month's ago also a Yamaha set from 1997, AX1050, CDC 835 and tuner. Complete overhaul.

For servicing still waiting:

Beocord 5500 (2x) 
Beogram CD 5500
Beolab Penta mk1
Beomaster 8000
Only if I have some spare time still to do:
Beomaster 1700
Beolab 1700
Beomaster 4000
Beomaster 4400

What a lot of time I could have to watch some favourite movies. They'll have to wait.
They call me a B&O addict over here, they're probably right...

Beobuddy
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Beobuddy replied on Sun, Mar 17 2013 5:57 PM

One thing I always tried to avoid was, replacing dial cord in the older centers/masters.

Dial cord is often used for tuning but also for volume and record level (BC4600).

 

But strangely. As I tried and made progress in placing new cords, I started to like this kind of work.

The dial cord of the BC 4600 was the more difficult one to place. Big slider, long length of cord and only having 2 hands Big Smile

Dillen
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Dillen replied on Wed, Mar 20 2013 6:19 PM

Beogram 8002.
Main board arrived from Texas.
A full recap, check for cracked solder joints plus the odd.
Tested in my mock-up stand. An intermittent failure in the tracking system was diagnosed to one of the servo motor bridge transistors. A fresh quad set of PU01 and PU51 replacement transistors cured this.

Martin

Dillen
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Dillen replied on Wed, Mar 20 2013 6:20 PM

Beomaster 1000.
Arrived from Sweden.
Early white key type. Owner said it didn't smell right.
He was right. It certainly didn't.
With the cabinet off, it was soon noticed that the mains transformer had an unusual, very dark color to it and the smell
seemed to come from these quarters.
Transformer secondary was separated and the Beomaster powered up with the mains transformer as the only consumer.
Pulling more than its fair share of current from mains the transformer heated up even if only powered for a brief moment and it started smelling even worse.
The dungeons held a good used original replacement transformer that, when fitted, brought life back to the poor thing.
A fresh pair of dial lamps, cleaning of the dial and underlying light diffuser, a replacement balance control knob to go
instead of a strange Philips-looking thingamabob and a dust blow-out finished this repair.

Martin

Dillen
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Dillen replied on Wed, Mar 20 2013 6:21 PM

Beovision LX2800
I normally don't do TVs. There are so many other repairers doing them and I never really caught interest in it.
But this was my own livingroom TV so I made an exception.
Family complained that there were light stripes across the screen one evening.
Sure there were.
Flyback cutoff stripes to be precise.
It came as no surprise to me, I noticed the stripes myself weeks ago, it's just that I hadn't watched enough TV myself to
be bothered, really.
Off with the rear cover, rotate the screen potentiometer back and forth a couple of times to remove oxidation inside, power on, adjust to flyback just disappears and put back rear cover. A 10-minute repair, family was happy again and I could
move on with other, more important, things.

Martin

Dillen
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Dillen replied on Thu, Mar 21 2013 8:18 PM

Beomaster 6000
Came from southern Denmark.
Owner told it often went into standby by itself.
Idle current was too high. Amplifiers were rebuilt with new trimmers and new capacitors.
Four fresh lamps to illuminate the volume dial and the two red tuning arrows, a check for cracked solder joints plus a
new belt for the volume gear motor and this one was playing nicely again. All very common for this model.
Apart from the goofy volume control, this is actually a very superb and solid build and aged caps and trimmers set
aside there's not a lot of electronic faults in these.

Martin

Dillen
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Dillen replied on Thu, Mar 21 2013 8:19 PM

Beocord 8000
This one came from Seattle. The owner put a contents value of USD 1200 on the shipping papers and
I was asked by the postal services to pay import fees and taxes to "import" the thing. I rejected and the Beocord was returned
to the owner who reshipped it with a more realistic value for a broken 1980s cassette tape player.
Problem was that, if you activated play soon after recording, the playback signal and the VUmeter deflection
would only slowly creep up to correct level.
A dedicated circuit mutes the playback amplifiers while recording and this muting did not instantly deactivate,
instead it was released gradually over about 30-50 seconds.
Problem component was diagnosed to 2C2, a small 10uF capacitor but all similar capacitors were replaced.
The deck was then treated with a good clean and lubricate of the mech. A fresh set of belts were
fitted and a new record/playback relay of the sealed type replaced the original not-airtight type that so often
cause problems. A check for cracked solder joints, always found at the large cable connector that connects the
mechanical section to the power supply board and it was shipped back.

Martin

Dillen
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Dillen replied on Fri, Mar 22 2013 3:50 PM

Beocord 5000 (49xx)
This one came from southern Germany.
It would light up the display but when a key was pressed the display just flickered and nothing else happened.
A missing 15V supply was soon diagnosed and the problem turned out to be the thick flex cable that
runs from the power supply to the motorized drawer deck. It runs through a series of stress relieves in the form
of flat metal stands and the cable had worn through to the copper around one of the metal stands, shorting the supply.
A good cable from a donor machine fixed this and the metal stands all received fresh lengths of shrink tubing to
ease the friction.
New belts, new record relay, the usual tapehead and pressure roller cleaning and off it went again.

Martin

Dillen
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Dillen replied on Fri, Mar 22 2013 3:51 PM

Beogram 4002
Came from a fellow Beoworlder living in Copenhagen
The deck ran very close to 45rpm at the 33rpm setting and far too fast at the 45rpm setting.
The platter belt was running on the upper flange of the motor pulley rather than the barrelshaped part of
the pulley body. Relocating the belt brought back the correct speeds but the belt wouldn't stay there, it kept
creeping upwards. Fitted the belt upside down, inside out and both, it crept upwards regardless.
I never saw this belt behavior before and I am not sure where he got the belt from but a new belt cured the fault.

Martin

Dillen
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Dillen replied on Sun, Mar 24 2013 6:12 AM

Beogram 4000
From Struer (of all places)
The carriage would travel home when stop was pressed but it wasn't braked correctly, instead the carriage crept
on a bit and returned towards the platter about 5mm before finally stopping.
The speed dials were found to be lit also in standby so something wasn't powering off correctly.
Problem was soon diagnosed to a shorted reed relay in the power supply.
This is not a common fault, reed relays are completely sealed and not affected by airs moisture.
I checked the circuits for current flows in case something had caused the relay switches to weld together but
found nothing.
A new reed relay was fitted and the thing played again.

Martin

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Dillen replied on Sun, Mar 24 2013 6:13 AM

Beomaster 900K
Owner bought it in Denmark and had it dropped off at my door for a complete overhaul before shipping
on to him in Australia.
Despite being purchased as "100% working, checked at B&O workshop", it had all the usual issues,
a hissing noise in one channel, two completely black dial lamps, weak FM reception, nothing special until
I discovered that the bass control potentiometer did nothing in one channel. That was a new one.
First the potentiometer itself was suspected but it measured fine on both tracks.
The problem turned out to be a missing 100uF capacitor near the potentiometer.
The boards solder pads revealed that this component was never mounted, it was simply left out from the factory.
Fixed this too and gave it a good oiling etc. and it went on the long journey.

Martin

vikinger
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vikinger replied on Sun, Mar 24 2013 9:32 AM

Hi Martin,

You might want to mention that white BM 2000 I picked out from that Danish small ads website and that you kindly agreed to repair for me.

What did the ad say.... lights not working ..... and you found that the lights and lenses had been completely removed!

The BM 2000 is still going strong. We just had that one slow fuse failure which was most likely an issue with the fuse itself because replacement solved the problem.

Graham

Dillen
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Dillen replied on Sun, Mar 24 2013 10:29 AM

Thanks for the input Graham, greatly appreciated !
I remember your lovely Beomaster but the recent repairs I list here are exactly that whereas your
Beomaster arrived here back in the earliest days of october 2009. Laughing

Great to hear that it's still going strong. They are wonderful and powerful receivers in a beautiful design.

Martin

Dillen
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Dillen replied on Sun, Mar 24 2013 7:46 PM

Beomaster 1900
From France
This one would not reproduce sound from the Tape input.
The muting signal was kept active when Tape was selected.
The problem turned out to be a wrong wattage lamp for the tape source indicator.
The wrong wattage kept the base-offset too high on TR6.
A few other lamps didn't work so the poor thing was treated with a fresh set of correct lamps and
a new pair of output stage idle current trimmers. The latter was still working but looked black from oxidation
and were of a known trouble-type that I like to replace on sight.
A few capacitors, the most fault-prone ones, were also replaced.
Beomaster 1900, being the first B&O thing I ever owned, always had a sweet place in my heart.

Martin

vikinger
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vikinger replied on Sun, Mar 24 2013 7:52 PM

Dillen:

Thanks for the input Graham, greatly appreciated !
I remember your lovely Beomaster but the recent repairs I list here are exactly that whereas your
Beomaster arrived here back in the earliest days of october 2009. Laughing

Great to hear that it's still going strong. They are wonderful and powerful receivers in a beautiful design.

Martin

How time flies!

Dillen
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Dillen replied on Tue, Mar 26 2013 4:07 PM

Beomaster 3000 (29xx)
I met up with the swedish owner on my local train station and he handed me this one for repair.
It kept clinging to P5. No other sources could be selected and standby didn't work either.
P5 it was regardless.
The problem was transistor TR37 which actually relates to the P4 source. It was leaking badly, conducting
current in both directions and a new transistor cured the fault.
Lacking a BF199 I fitted a BF240 which worked just as well.
Met up with the owner again a few days later and handed over the Beomaster.

Martin

Dillen
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Dillen replied on Tue, Mar 26 2013 4:07 PM

Beomaster 4000
From my own collection.
This one had a complete overhaul, new capacitors, trimmers etc. but still it would go into a very deep and heavy
self-oscillation at around 10Hz or so when the volume control was set above a certain level on the ruler, like 3 or 4.
It would slowly fall back to rest below this level.
I scrutinized the boards and found component 136, a 2,2Kohm resistor that looked a little cooked. Not a lot, just
slightly darker than its brothers.
A further diagnose showed that component 137, normally a 9,1V zener, had been replaced by a previous repairer.
This component is a bit of a weak spot in this type of Beomaster so finding a previous repair here is not
uncommon but the repairer had fitted a 1N4001 which is just a normal diode rather than a zener.
It had 42V across its pins so was not exactly a happy camper.
Transistor TR10 and the dark resistor was replaced and a correct zener diode 137 was fitted.
What a difference this made.

Martin

BO
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BO replied on Tue, Mar 26 2013 4:30 PM

I really enjoy reading this thread! Keep on Big Smile

//Bo.
A long list...

Dillen
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Dillen replied on Tue, Mar 26 2013 7:45 PM

Beovox S30 type 6301
A single speaker arrived here for repairs. The owner claimed it had gone almost silent.
He couldn't have put it any clearer. Only the tweeter produced sound.
The woofer was dismounted from the cabinet and checked, tested fine.
The crossover board was then inspected, revealing one of its capacitors to have physically blown one end out.
The lead and rubber insulator just hang there, connected to the board at one end and nothing at the other.
A fresh set of capacitors saw the speaker playing again and I called the owner and asked him to bring
the other speaker in too so it could receive the same treatment.
They are very nice speakers for their size. Wonderfully balanced.

Martin

Dillen
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Dillen replied on Thu, Mar 28 2013 7:01 AM

Beogram 6500;
A nice white version arrived here for repairs as part of a very nice Beosystem 6500 bought by a fellow Beoworld'er.
The carriage no longer moved as intended. The carriage wire had come off and was found tangled around
different mechanical parts inside the Beogram.
A repair to this was made and the wire fitted back where it belonged.
The start button on the vertical front didn't work. I took it apart and gave it a close look; It's not uncommon to find
a good amount of oxidation in these springy bronze contacts but this one had blackened completely and what was
once copper tracks on a small circuit board was now a green-ish mess with no conduction. Looked like something
had been spilled down here.
The dungeons provided a nice replacement board.
A fresh platter belt rounded off the repair chapter. The show, however, continued a bit further as new capacitors
found their way to the built-in RIAA pre-amplifier to bring the player up to par.

Beocord 6500;
A white one was delivered in together with its matching relative above.
The deck sounded very strange when power was applied, like something was whipping around, hammering a bit
on something else and it didn't run.
This was a three-belt version and the owner had replaced the motor belt with a nice green elastic band that had come
off and tangled itself around the motor pulley, leaving a fairly large free-swinging loop of elastic band to whip around
when the motor was running.
A fresh belt set was fitted and a minor modification was made to the motor control circuit, which ideally should be
introduced to all decks of this type due to the original circuit construction of the protection system being marginal.
A good cleaning of the capstans and pressure rollers and out it went.

Beomaster 6500;
One more white Beosystem 6500 component from the above mentioned family.
Arrived here sounding a little tired.
Needed a fresh muting relay and a check for cracked solder joints. The latter are almost always found on the output
stage driver transistors and occasionally at the amplifier power supply relay.
Nothing uncommon.
Fresh capacitors for the low-voltage power supply, the amplifier and preamplifier plus a pair of new
trimmers for the idle current adjustments rounded off this restoration.

Beogram CD6500;
The final component in this white Beosystem would never open its drawer. It would only move inwards, never out,
so playing CDs would have been difficult unless one had already been loaded.
A repair was done to the damaged drawer switch and the laser lens was cleaned which brought back normal operation.
Further work included new capacitors for the servo board, a good check for cracked solder joints - there's almost
always a good bunch of them - and a fresh drawer belt.

Martin

Dillen
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Dillen replied on Thu, Mar 28 2013 6:40 PM

Beolit 600
The old version with rounded corners. A grey one, practically mint.
The korean owner claimed it was noisy and indeed it was. Regardless of the volume control a fairly audible and
quite annoying constant hissing was emitted from the speaker.
The reason turned out to be a bad germanium transistor. It gave itself away when subjected to a blast of
cooling spray. I blasted one of the candidate transistors at a time and suddenly the hissing almost disappeared.
Basic and elementary fault finding, really.
It's not uncommon to find noisy germanium transistors and certain types seem more prone than others.

Beolit 600
Same version as the above, only this one was green.
I don't do that many Beolits so having two of the same type on the bench at the same day is highly unusual.
This one had a note on it from the owner in New Jersey stating "intermittent FM reception".
It was completely silent on FM on the bench. A dab with a pencil onto one of the IF transistors saw the radio
bursting into life for a brief moment. The transistor was replaced and no other faults were noted. It played along
happily while I cleaned up the workbench for the night.
What nice radios these Beolits are and what a pleasant sound they produce.
I have a few of them in my collection, must see if I can find time to do one of my own someday.

Martin

Dillen
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Dillen replied on Sun, Mar 31 2013 10:01 AM

Beogram CD X
This one came from nothern Sealand.
Owner complained that it had started sounding "strange" a couple of weeks ago and now it wouldn't play anything at all.
How right he was.
First thing to check in these wonderful machines is the rivet vias. Connections from one side of a board to the other
in the form of a soldered rivet running through a hole in the board.
Temperature and vibrations cause these fairly massive solder joints to develop internal cracks, usually causing
progressively worsening intermittent failures. The rivets are found in both servo- and audio circuits so symptoms
are plentyful and often "unexplainable" in terms of defective components.
A repair to this issue was exactly what was needed in this one.
I am always impressed with the pleasant sound produced by these 14-bit players. So easy on the ears.

Martin

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Dillen replied on Mon, Apr 1 2013 11:47 AM

Beogram 6500
Arrived from Singapore.
Had a note on it stating "Carriage not moving correctly".
Very correct. The carriage wire had snapped its plastic holding point and the wire had tangled around different
mechanical objects inside the Beogram. Third individual with this fault in just a couple of weeks. Don't dare to
guess how many decks gets thrown out because of this.
The fix for this, in the form of a screw from below, through a nearby hole in the carriage foot, and a washer and
nut on top for the wires spring to snap on to, has been shown in these forum pages previously and was carried
out in this deck.
A new platter belt was also asked for.
According to my notes I did a power supply repair and replaced the platter motor in this deck back in august 2001.
Apparently it still sees a lot of use and it was nice to see it again. Maybe I'll see it again in 2025.
A good testing to ensure proper operation before winging it back around the globe.

Martin

Barry Santini
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I really enjoy this too, Martin!

B
BO
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BO replied on Mon, Apr 1 2013 12:35 PM

Dillen:
I am always impressed with the pleasant sound produced by these 14-bit players. So easy on the ears.

I must agree to this. I recently had one. Very pleasent sounding. It uses the Philips CD104 (CDM1) mechanism with double TDA1540 14-bit mono dac's.

 

 

//Bo.
A long list...

Friedmett
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Thank you Martin for the low down on my "new" white 6500 system. Did you forget the MCP6500? I am still on the hunt for some hinges.

 

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