BeoGram

Re: 4004 can't find a 45?

tournedos — Sun, 22 Jan 2012 13:26:37 GMT

Rapidroy:
My guess, cold solder joint?

Quite possible - apart from obviously broken components, bad caps and bad solders probably cause the most problems with old B&O kit. Bad solders are more common in TVs because of thermal stress but you often see them elsewhere too. Wave soldering wasn't that advanced back then, and occasionally you see a problem that was hand made in Denmark

Hope you can now enjoy the deck for a long time

Re: 4004 can't find a 45?

Rich — Sun, 22 Jan 2012 13:26:08 GMT

Very cool, Roy. Way to keep at it, and thanks for supporting the site by upgrading to silver.

Re: 4004 can't find a 45?

Step1 — Sun, 22 Jan 2012 12:57:39 GMT

Great :)

Re: 4004 can't find a 45?

Rapidroy — Sun, 22 Jan 2012 11:40:16 GMT

All is grand in Beoland! I pulled TR5 to test, it tested good, put it back. Put the belt and platter back on, put a 45 on just for fun, pushed start and the tonearm went right by the 33 part, it did the auto switch speed to 45 and dropped on the 45 record!!!! My guess, cold solder joint?

Re: 4004 can't find a 45?

Rapidroy — Wed, 18 Jan 2012 15:18:48 GMT

I found it. Thanks

Re: 4004 can't find a 45?

tournedos — Wed, 18 Jan 2012 14:38:32 GMT

Rapidroy:

I bumped up to silver membership and still no schematic?

As I said earlier, look in the 4002 manuals. One of them (can't remember which) contains the 4004 and the scan quality is also much better than the excerpt you posted earlier.

Well appreciated

Re: 4004 can't find a 45?

Rapidroy — Wed, 18 Jan 2012 14:35:09 GMT

I bumped up to silver membership and still no schematic?

Re: 4004 can't find a 45?

Rapidroy — Tue, 17 Jan 2012 00:08:30 GMT

I changed

1c19 4.7

1c20 1.0

1c21 4.7

no change in operation. darn. I like to change things one thing at a time, then test to make sure I haven't made things worse.

Re: 4004 can't find a 45?

Rapidroy — Mon, 16 Jan 2012 13:20:39 GMT

I disconnect the light in the arm, pressed START (nothing on platter) platter spun up to speed, tone arm moved to edge of platter and dropped tonearm at the 33 area. I picked up a couple caps that load up to tell the arm stay up or drop down, the ESR meter showed being marginal I'll give them a try later today.

btw: I was a paid member but money is a little tight right now, I did try to pay but they don't take PayPal (I sold some stuff and my PP account has a few bucks in it).

Re: 4004 can't find a 45?

Step1 — Sun, 15 Jan 2012 19:48:32 GMT

Firstly, it would be great if you helped this site and became a silver member (or gold with fantastic benefits) and then you would have access to the diagrams.

Now, a quick way of tracking the fault either side of the detector circuit is to disconnect the detector lamp from the circuit. I recomend removing one of the wires that terminate on the pcb near the solenoid (please insulate and safely tuck away). If the arm still drops then it is a problem with logic. If the arm does not drop it is a problem with the detector circuit.

As Mika suggested an oscilloscope is required to fault find, however testing / replacing the electros in the faulty section is possibly your only option. Just do so carefully and methodically to minimise the introduction of new faults!!

mean't to add capacitor kit is available from Martin (user name Dillen)

Re: 4004 can't find a 45?

tournedos — Sun, 15 Jan 2012 15:29:55 GMT

Rapidroy:
I have the service manual but it does not have a full schematic. I don't think anyone has a FULL schematic for this TT.

The same place where you found that document, which is stolen from this site, probably hosts other service manuals stolen from this site as well, so look for 4002 too. The 4004 is very similar to the later DC motored 4002's, with the addition of the simple remote control logic.

There are numerous minor revisions of each model, so be flexible when reading the diagrams, as the component numbers don't always match.

Rapidroy:
what does "Rep. BL " mean?

It means to replace that component, I think. But you shouldn't blindly follow the troubleshooting diagrams, as just like any service manual, they were designed to help when these decks were new. Old age problems can manifest themselves differently, often in ways nobody could see coming decades ago. Replacing caps that are obviously faulty should be a good start.

Ultimately, you need to follow the signal from the detector arm and see where it gets lost. It can't see the ribs on the platter now, and the problem can be as basic as a too weak or optically mislocated bulb. It is unfortunately quite hard to get right without an oscilloscope. The full schematic shows oscillograms at several points in the amplifier circuit.

Re: 4004 can't find a 45?

Rapidroy — Sun, 15 Jan 2012 14:33:38 GMT

yes I know what "1TR5" is, but look at the center of the pic I posted what does "Rep. BL " mean? I have the service manual but it does not have a full schematic. I don't think anyone has a FULL schematic for this TT. I found some high ESR's on a couple of cap's so I'll replace them and see.

Re: 4004 can't find a 45?

chartz — Sun, 15 Jan 2012 11:44:24 GMT

You really need the diagram! 1TR5 means transistor TR5 on PCB one.

Re: 4004 can't find a 45?

Rapidroy — Sat, 14 Jan 2012 12:17:55 GMT

anyone know what this means? "Rep. BL (1TR5)" I'm thinking that my problems are in the detector arm circuit. But not having a schematic I'm lost.

Re: 4004 can't find a 45?

Rapidroy — Fri, 13 Jan 2012 16:01:25 GMT

do the transistor's 1tr6 or 1tr8 have a habit of going bad?