BeoGram

Re: Beogram 4002 TYPE 5503

auric — Sun, 27 Jan 2008 17:44:16 GMT

The deck is intermittent. Somtimes it will shut off completely, other times half way

ON 0TR1: (OFF Condition)

base voltage is 3.6 V; emitter voltage is 3.0 V

Other times:

base voltage is 0.5 V; emitter voltage is 16mV

C2 electrolytic has already been changed with new one.

I notice that even with deck "OFF" R1 is warm.

Derek

Re: Beogram 4002 TYPE 5503

Dillen — Sun, 27 Jan 2008 17:15:42 GMT

Yes, it sounds like it doesn't go completely off.

There's a couple of diodes in that circuit and also a couple of electrolytic capacitors.
Can you give me the emitter voltage of the first transistor 0TR1 in the "OFF" condition ?

Martin

Re: Beogram 4002 TYPE 5503

auric — Sun, 27 Jan 2008 16:00:26 GMT

Martin:

I think I'm good on the transistor. The online cataloge where I looked it up crosses the 2N5034 to a 2N3055.

1TR1 - 39 volts on the collector, 23 volts on the emitter with the arm away from rest position (ie ON).

In OFF position (arm at rest) collector reads 42 volts DC, emitter has 2.4 volts AC

The units gets pretty close to shutting off (sometimes), but not fully off. You can still feel the motor jitter.

Derek

Re: Beogram 4002 TYPE 5503

Dillen — Sun, 27 Jan 2008 13:20:14 GMT

Alright so far.
(I have a couple of good used 2N5034's in stock if you need).

From the voltages, it seems that the transistor is commanded ON all the time.
On to 1TR1 which is the driver, it has a fuse in the collector.
Let's see the voltages on all three leads.

Martin

Re: Beogram 4002 TYPE 5503

auric — Sun, 27 Jan 2008 01:08:13 GMT

Hi Martin:

I replaced the power transistor and things seems to have improved slightly.

When you hit stop, the carriage returns and the 33 rpm light dims. The motor will stop most of the time but sometimes rather stoping it sits there jittering as if there is not enough voltage to overcome the inertia for rotation.

For those following this thread, the original transistor is a 2N5034. This is an open style TO-3 transistor. It looks like a TO-220 case mounted in bracket so that it can be screwed down in the TO-3 style. Anyhow it appears that this transistor is no longer available. The replacment is a 2N3055.

Before the replacement I was getting 38 volts on the collector vs gnd. and 23 volts on the emitter vs gnd. After replacement I'm getting 39 volts on the collector and 23 on the emitter. I removed the old transistor and using the diode check function on my digital multimeter I was getting a 0.3 volt drop across base to emitter and base to collector, which is bit low so I replaced it.

The voltages are still out of your suggested range but it appears that the transistor is working.

Will keep working at this!

Derek

Re: Beogram 4002 TYPE 5503

Dillen — Fri, 25 Jan 2008 14:26:59 GMT

I think so.
As already stated, at present I don't have a Beogram of the type 5503 here but I have a found a photo of one and that transistor would be my guess. Check also that no wires are shorting to the transistor housing.

Martin

Re: Beogram 4002 TYPE 5503

auric — Fri, 25 Jan 2008 13:44:47 GMT

Hi Martin:

-Command Panel checks out fine. No stuck keys. (I disassembled the entire panel and reglued the keys as some of the plastic tabs beneath had fallen off.)

-The deck is completely responsive except for:

1) the constant running platter

2) sensor arm not lit

3) tone arm lift/drop won't respond (likely because sensor arm not lit)

4) unit won't turn off (at rest position after presssing off - I can still move tone arm LEFT and RIGHT using the two keys)

Hitting Start sweeps the tone arm across the deck, switches speed to 45, and automatically returns to rest when no LP is detected.

I'll check the switching transistor tonight. Is it the big TO-3 transistor by the motor?

Derek

Re: Beogram 4002 TYPE 5503

Dillen — Fri, 25 Jan 2008 13:33:34 GMT

The constant running platter motor is a sign that the
22.8V power supply is constant on but the sensor arm isn't lit
because no start command was given.
No stuck keys at the operator panel ?
Check the 22.8V supply switching transistor, I don't have a Beogram
of that exact type available right here but it's 0TR1 in your machine
and it's shown to be located away from the PCB.
Check the voltages at the emitter and collector respectively with ground as reference.
We would expect something like 32-34 Volts on the collector and the 22.8 Volts on the emitter if the transistor is OK.

Martin

Re: Beogram 4002 TYPE 5503

Peter — Thu, 24 Jan 2008 01:55:40 GMT

The manual for the 4002 type 5501/2 is on site. It is a big one - over 10MB and had to be loaded by Van as it exceeds the limit for me to upload. The 5503 is another market variant of this model. You need to be a gold or silver member.

Beogram 4002 TYPE 5503

auric — Tue, 22 Jan 2008 23:49:17 GMT

Hi:

Does anyone have a copy of the schematics for the Beogram 4002 Type 5503?

I have the manual for type 5523 however it appears quite different from 5503.

I'm trying to troubleshoot mine. The sensor arm won't light up (bulb is ok) and the unit continues to remain on even after slide mechanism returns to rest.

Any assistance/advice would be greatly appreciated!

Derek