Bullet VM30 combo, GDR from 1990

But looks more 1970s . Anyone familiar with strange transistor. capacitor and these IC markings such as "X2 080" ,"X8 761" ,"TL 761" (not opto) ,"X8 082" ,"X6 081" ,"X6 082" , V4007D (not CMOS 4000)

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N_Cook
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Found in an old VEB Kombinat Mikroelektronik databook:

B080D = TL080 B081D = TL081 B082D = TL082 B761D = TAA761 V4007D = CD4007UBE

Best regards

Piotr

Reply to
Piotr Piatek

markings

Thanks for that, I'd only assumed there was no use for 6 off CMOS inverter packs, assuming they were more likely to be quad opamp packs.

Do you know why there are all thes +digit numbers on the ICs transistors and electrolytics ? the 2 main TO3 output Tesla devices are marked KD607 but also X69321

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N_Cook

thes +digit

should read

these X + digit

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N_Cook

Sorry, I don't know. Perhaps they are date codes.

Piotr

Reply to
Piotr Piatek

No idea about the electrolytics. On the semiconductors, it's the marking for production month and year (but I don't have the code handy).

The KD607 is a Czech npn power transistor, 10 A, 80 V, 70 W, designed for AF power amps.

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cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
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Joerg Wunsch

and

I only have one German data book , ECA from 1987 and it does not list the final uncertainty. An E-line size or varicap type package of a diode marked 32 VV or 32 YV, 32 volt zener ?

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N_Cook

Any chance to take a photo? My guess is it's an SAY32 which is a simple silicon small-signal diode.

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cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
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Joerg Wunsch

with a 2.5mm nut for scale

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the pins are flat not round

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N_Cook

with a 2.5mm nut for scale

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the pins are flat not round

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N_Cook

I confirm that it's an SAY32 diode (25V, 50mA).

Piotr

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Piotr Piatek

simple

Probably those are 32V zener. There are 2 more of that package on the preamp. These labelled 15 X4 and next to the +/- pass transistors for the preamp +/- rails so probably 15 Volt. I will be able to power up tomorrow and see

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N_Cook

Doubtful, as 32V is not a standard E24 value.

Yes, it's possible that they are 15V Zener diodes of type SZX21/15, because the databook doesn't list any other diode with a part number

  1. I also remember that these diodes were marked only with the voltage value, for example 9,1 for a 9.1V part.

Piotr

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Piotr Piatek

"N_Cook" schrieb:

Yes, it's an SAY32. The YV is -- again -- the datecode only. The SAY is left off from the marking, because it's been obvious, so only the

32 was really labelled.

I uploaded the respective databook page to:

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cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
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Joerg Wunsch

It's a SAY32

Some more data sheets for components from GDR:

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KD607:

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XL

Reply to
Axel Schwenke

Certainly the right package. I've now powered up and the 15 marked ones are the zeners for setting the

+/- preamp rails. There was a burnt section of the ground track between the secondary ps side of the preamp and the signal side. Probably due to operator "error" and have replaced with a fuse there.

The siting of the ones marked 32 maybe for overvoltage sensing , but not normally in service.

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N_Cook

second attempt

Certainly the right package. I've now powered up and the 15 marked ones are the zeners for setting the

+/- preamp rails. There was a burnt section of the ground track between the secondary ps side of the preamp and the signal side. Probably due to operator "error" and have replaced with a fuse there.

The siting of the ones marked 32 maybe for overvoltage sensing , but not normally in service.

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N_Cook

"N_Cook" schrieb:

(Why? Your first attempt worked pretty well.)

Yes, the Zener diodes were just marked with the voltage in the first row, and the production date in the second row. The prefix SZX 21/ was implied. Kinda hard to distinguish them from the plain diodes marked 30/32/40/42, but as the maximal voltage for the Zeners was an SZX 21/24, there was just no collision in the numbering.

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cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
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Joerg Wunsch

Repaired now, but for the archives there is a safety issue with these amps. The earth bond wire to the amp chassis is fine but the bond to the front panel metal is very poor, just a brass rivet to the phenolic of the pcb, of a few ohms drop over the years. Needs redoing to the metalwork properly.

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N_Cook

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