Mic and Line LED not working

[tlmaen]

Hi,
have a lot of Channels were the MIC LED (or sometimes the Line LED) is not working.
Figured out it must be the Logic card. On that card it must be TR 23 and TR 24, BC212 Transistors (traced it backwards and it matched the Pinouts of the Card sheet).
I replaced the BC212, but the LEDs are still not working.

When the BC212 are being faulty, do the fry the LED?
Don't want to replace the LED yet, as its not that easy with the cables and glue.

Thanks,
Tilmann

[walrus]

Did you use the required L type transistor BC212's, as they have a different pinout to BC212A/B/C's?
If correct, maybe swap T11 on the logic card.

[tlmaen]

Hi Kevin,
yes, I used the BC212L, because I had them in my Spare Part Box wich came with the Console.

But Thanks for the Info, I probably would have ordered the usual ones...

It works now, it was a shorted LED (only did one channel with this fault today).

Thanks,
Tilmann

[walrus]

Never seen shorted LED's before.
Early Neve V's had a problem with the green tombstone type LED's going dim!

Hopefully the rest will be simple fixes too.   

[horizonsound]

I've seen where someone removed the rear washer on a stepped mic gain pot (for a 291 preamp), which in turn contacted the leg of the adjacent LED, shorting it to the front panel.

The result was a toasted DIL resistor pack on the logic board.

Anthony.

[tlmaen]

Interesting. I have retrofitted switches instead of a Mic Gain Pot.
Will check that.

Thanks,
Tilmann