Old School LED Help Needed

[dorkjackson]

Hi All-
I have an Allen & Heath Syncon A mixing console that had been highly modified. The LED meter bridge is basically a custom job. It was working when installed, but one of the PSUs recently went kaput and took out the logic control board. This mod was done in the early 80s (I think) so if anyone can point me in the direction of an engineer or tech with old school LED prowess, I would certainly dance a jig.
Thanks to all in advance!
DJ

 

[Van]

Are you speaking of the LED VU meter? The reason I ask is that you can find a 1001 kit's videos and other DIY sources for an LM3915 VU meter with outputs that range from three to 10-12 LEDs.

 

[dorkjackson]

Are you speaking of the LED VU meter? The reason I ask is that you can find a 1001 kit's videos and other DIY sources for an LM3915 VU meter with outputs that range from three to 10-12 LEDs.

Yes. It's for the VU meters for the entire console. We would like to repair rather than replace, but if you could send a link, at least it's a resource. Thanks for your reply.

 

[Van]

https://www.newegg.com/Product/Prod...Lki5VVmz1YienvNf1lBoCJgwQAvD_BwE&gclsrc=aw.ds

https://www.parts-express.com/yuan-...source=google&utm_medium=cpc&utm_campaign=pla

 

[FMEng]

That's a recording console. There are forums for vintage recording gear, and you might have better luck there.

If all else fails, try replacing the chips in the metering section. If they are socketed, it's an easy and job. If the circuit design was borrowed from a Syncon B, the drivers are LM339. If the design was not borrowed, I would expect to find LM391x series chips, which have been the popular meter driver since the late 70s. If there is meter switching involved, look for CD40xx series CMOS chips, which are well known to fail from over voltage.