Forum Replies Created
-
AuthorPosts
-
DillenModeratorWhich version of Beocord 9000 do you have – serialnumber?
Martin
DillenModeratorWill the Beocord play back tapes recorded on other decks/factory recorded tapes?
Does tapes recorded on the Beocord play back correctly on another deck?Martin
DillenModeratorCan we see a photo of your Beogram with the platter height visible?
Martin
DillenModeratorA very low platter/subchassis setting can often cause wow.
Reason: A 12″ record is a larger diameter than the platter and the wow comes when the record touches the
surrounding surface – gradually increasing as the tonearm and carriage move inwards, shifting the subchassis’ center of gravity.
First tracks play fine, later tracks not.
The solution is to tighten up the suspension a little at the left/rear.Don’t overdo.
Make sure the subchassis is still able to move freely.Martin
DillenModeratorFrom same territories, generally, yes.
Refer to the part numbers in the service manual and the 4-digit type numbers found on the serial number labels to make sure.Martin
DillenModeratorIs the amplifier sections powered at all?
Bad relay?
Blown fuse?
Cracked solder joints where leads go to the relay board?
Open ceramic resistor on the relay board?Martin
31 August 2022 at 16:37 in reply to: Beomaster 8000: Would there be any advantage to screwing a heatsink to TR211/207 #38749DillenModeratorNo! It’s made like this and it’ll work fine.
(Actually the best and most stabile operating temperature for many semiconductors of this sort is 60-70 degC).Set the idle current as adviced in the service manual.
Final adjustments are done with the Beomaster under normal working conditions (warm).If the idle runs astray (keeps increasing, also after a few minutes) there is a problem
somewhere, – most likely lack of thermal coupling from the output stage darlingtons – or from the temp. sensing transistor in the constant current generator – to the cooling fins.(Never run an amplifier like this without the cooling fins – it’ll do a thermal runaway).
Martin
DillenModeratorThe rush-in current at power up is quite substantial. Not all voltage converters like that.
A dead prescaler usually won’t affect the function of the tuner. It would merely mess up the displayed frequency.
Check the cables to the tuner boards, at least the screened one that goes to the CPU board
is easily pulled off inadvertently.
Check also the solder joints at the two tuner boards interconnecting plugs.Martin
DillenModeratorKeep in mind that the record is typically thicker around the perimeter than in the actual playing area,
– to ensure the needle moves inwards in order to find the groove – rather than outwards.Martin
DillenModeratorNo, these are not ICs you would enjoy replacing just for the fun of it.
Put a scope on the control pins and see if everything goes to binary plan when you run the volume up and down.
If it does, swap the two ICs to see if the problem moves to the other side.
If it doesn’t, find out where the missing bit went missing, bad connectors, cracked solder joint, broken cable etc.Martin
DillenModeratorMissing bit to one of the volume control ICs.
Or a bad IC.Martin
DillenModeratorThere are several, slightly different, versions.
Three of the ones shown here have different transistors, and the last one is an entirely different (earlier) version, mainly seen in 41FV and 42FV.Martin
DillenModeratorCould also be a Siemens SAB8032A-P or a third type I don’t recall right now.
You will have to look inside.
When you know the type ask at Beoparts-shop. Even if not listed, quite often old stock can
be found there which is much better than buying asian counterfeits off Ebay etc.Martin
DillenModeratorSounds like a Beocenter 7000 rather than a Beomaster 7000.
Martin
DillenModeratorDifferent transistors and diodes were used in production.
Indeed OA81 are found in some versions.Mexking, I still have your RIAA here, remember.
– And it actually has OA81 fitted.Martin
DillenModeratorThey are not 22uF.
A 1960s 22uF film capacitor would be the size of a beer can.
Look again. Rotate it or lift one end away from the PCB.
I’m sure it says 0,022uF.
That’s quite normal. As is 22000pF, which is also 22nF.
Just like the one next to it says 1uF if you cover the “0,”.Some of the most reliable capacitors on this planet, those “Mullard mustards” are.
Martin
DillenModeratorSure it doesn’t say 0,022uF?
That would be 22nF.Martin
DillenModerator1
OA70 are germanium diodes.
Not schottky! (No schottky in power supplies).2 and 3
They are styroflex capacitors.
If you cannot find styroflex, you can fit polyester capacitors for 2 and ceramic for 3.Martin
DillenModeratorFor the older products, there is no link between serial numbers and production dates.
Beomaster 8000 was produced 1981-83.Martin
DillenModeratorFrom serial number 2554003 the monitor function was moved from TP1 to TP2.
This required a change to the slave CPU, the preamplifier and the socket panel.Martin
-
AuthorPosts
