Lyrec 532 tape card no output

[Manitou]

Hi folks,

My old Lyrec machine has started to develop issues on a couple of cards and I wondered if anyone on here might be able to shed some light on them.

All the cards bar 1 playback in sync mode and a couple are not playing back in repro mode. +/-15v power from the machines motherboard is good. When I swap the cards round to other slots the faults follow the cards.

I've attached the schematic for the amp cards (sorry it is split across 4 pages). Should I start with checking the power to the repro and sync amp ICs? Is it likely the ICs themselves are goosed, or is it more likely to be bad caps on the cards? The machine is probably 25-30 years young. Any advice would be welcome. Cheers!

 

[Bo Hansen]

Manitou,

Since the error follows the PC card when you move it around, it should be some ware on this big audio card.

I would start by checking for bad dray out electrolytic capacitors in the repro/ playback amp.
Btw, there shall be approx. -4,6 volt on transistor TS8 emitter leg, if the repro amp work ok.

There can also be oxide on the small equalizer PC card connectors, or if any of the FET switches for equalizer or playback/sync is broken.

--Bo

 

[Manitou]

Thanks Bo!

I'm hoping to get time to investigate these points over the weekend. I'll post back with how I get on 

 

[Manitou]

Well here is a very belated update on these cards 

I have now gone through all the voltages you pointed me to Bo. Thanks for that!

I figured out that some of the Electrolytic caps on those circuits were faulty from the test points where the voltage readings were out. They have now been replaced & all cards are now operating in sync & repro perfectly. So a big thank you Bo 

Now it's playing perfectly again at last I've also noticed the erasure on 4 of the cards is pretty weak. The voltage at the erase current test point reads low compared with the good cards.

Anybody got any ideas about where on the boards I can poke about to investigate this problem & what I might look for???

I'll try not to take such a long time this time... :-X