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DillenModeratorIsolating the secondary merely means disconnecting everything on the secondary (load) side of the transformer.
Doing this will confirm that the humming is caused internally in the transformer and not as a result of a too high load.Replacing the transformer is the only cure.
Having siad that, the humming transformer will continue to work technially with no problems for many
years on, but of course the humming can be annoying.Martin
DillenModeratorIt can be difficult to spot the crack in the worm gear.
I have seen this several times, and I suggest you look again.
Or simply pull off the gear and glue it back on using a good 2-comp. epoxy.Martin
DillenModeratorLubricating the motor bearings is not that easy;
Clean out in acetone bath for 24 hours, slush around every now and then to flush as much dirt and dry oil remains out of the pores in the metal as possible.
Allow to airdry for a few hours.
Submerge in sinter oil containing the correct and required additives.
Pull vacuum until bubbling stops.
Release vaccum and leave bearings in the oil for a few hours to allow the oil to soak into the pores.-And if the bearings are already worn from running without proper lubrication, even for just a brief moment, they won’t
ever be any good again.Easier is to simply replace the bearings (read here):
https://www.dksoundparts.com/product/motor-bearings-set-for-beogram-motor-with-3mm-spindle/Martin
DillenModeratorReverse spinning at mains on could f.e. point to lack of input to the processor from the tacho-sensor.
The deck initiates the motor circuit by reversing it ever so slightly to see the feedback from the tacho sensor.
With no feedback, the reversing command will not stop.Could be a bad sensor-opto but is more likely to be a cracked solder joint somewhere – at the ribbon cable or at the CPU socket. In decks with the extra IC 4013 inside the CPu housing, this IC can also be at fault. A scope will tell.
Ripple on supply voltage(s) can also cause strage things. Did you replace all capacitors in the kit?Martin
DillenModeratorYou don’t state if your deck is a DC- or AC-motor version, but in general:
Dry motor bearings (if never replaced it’s time now).
Bad speed relay (if never replaced it’s time now).
Bad speed trimmers (if never replaced it’s time now).
Bad contact in speed fingerwheel-trimmers (clean them anyways).
Cracked solder joints at PCB connectors (later decks only), particularly the one for the speed dial panel.
Bad TVS diodes in motor (not that common but it does happen. AC-motors don’t have them).
Any combination of the above.Martin
DillenModeratorIt will not work.
The “old” and “new” datalink systems are not compatible.Martin
DillenModeratorYou can glue on wooden dovel pins instead. Paint them black afterwards.
Martin
DillenModeratorThe lamps are correct.
Weak rectifier would be my guess. Wouldn’t be a first.Martin
DillenModeratorCheck the fuses for the amplifier section. (F3/F4 I think).
Sounds strange, I know – but try it.Martin
DillenModeratorMeasuring with an ohm-meter (“DC-resistance”) will not give the impedance (“AC-resistance”).
It may come close, but don’t count on it.Martin
DillenModeratorAn IF stage slightly off correct alignment can cause this.
As pronounced as this, it could be the last stage before the detector.
Don’t attempt to do any alignment unless you have the proper instruments for it.
There are ways to do it without, but it usually requires more than average experience.I don’t think it does, but if your Beomaster uses AF116/AF117 transistors in the IF stages, one or more of them could also be bad (or just weak). AF125/AF126 are not as fault-prone.
Martin
12 August 2024 at 15:57 in reply to: beomaster 1000 ( type 2317 ) restoration & improvements? #58200DillenModeratorWhat, in your opinion, would be a better RIAA curve?
Martin
DillenModeratorThe damping grease is a bit too thick for this.
The action will be smooth, but the timing may not allow for complete opening and closing.I use this stuff for the large gear and the four rollers (practically every place where plastic works against metal):
https://www.dksoundparts.com/product/grease-for-carriage-metal-rails-etc/
Martin
DillenModeratorRight kit:
https://www.dksoundparts.com/product/electronic-service-kit-beogram-cd5500-cd6500-cd7000/Any good repairshop should be able to do it.
Martin
DillenModeratorIf the drive refuses to read the disc, the first thing to replace is C2103 (and the rest of the electrolytic capacitors on the servo board).
C2103 MUST be a blue axial Philips or BC. I know it sounds strange, but it is a fact that not just any capacitor from any brand will work in this position.
The capacitance is not that important, it could just as well be a 47uF, but fitting anything but a blue Philips/BC cannot be guaranteed to work.
It has certain filtering properties not found from other brands.
A convenient kit is available from Danish Sound Parts containing the right capacitor.Martin
DillenModeratorMartin
DillenModeratorC2103 must be a blue axial Philips/BC. That’s the only type I have found to be guaranteed to work.
I suppose you would have known it, if you fitted this type, so I suggest you replace it again, this time with such one.Martin
DillenModeratorWhat did you fit as C2103 (brand/type)?
Martin
DillenModeratorA transformer will always hum a bit. It’s in their nature.
New correct rubber feet are available – visit our sponsor Danish Sound Parts.Martin
DillenModeratorThe transformer is at the back left.
But it is most likely what you hear.
Does the hum go away when you lift the Beogram?
Has the deck lost its rubber feet?Martin
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