metering trouble on a trident trimix/series 70

I have a little 16 input Trident trimix here i'm fixing for a friend. The previous owner did all sorts of mods to the thing and my buddy wants it put back to stock. I'm pretty much done, she's working fine and sounding great, BUT.....

I'm having a bit of trouble with the metering. each channel has a 5 segment LED meter, all of them are working, but any signal on any channel appears on any other channels meter, usually at a higher level than on the channel the input is coming from. If I mute the master outputs, the metering works perfectly. Unmute and they go crazy again.

I don't have any more crosstalk than usual, the meters just act funny. anyone know what could cause this?

I have a trimix, & the problem must be something to do with the mods that have been done. I'm fairly sure that the meter can be place pre or post fader, so it maybe worth looking at the link that programs this. He must have linked it to a buss somehow.

By the way be very careful with the meter driver chips SN16880n. They are really difficult/impossible to get. If you have any spares I've been looking for 2 forever. Anyone ??

The links for the meters are set to post fader, which i believe is factory.

there were no mods to the motherboard that i can tell, all of the mods were done to individual modules in the master section. the channels are stock, and are actually the mkII channels out of a series 70. the channels and their meters work fine in a 70, and the mkI modules he has work fine in the 70 and show the same behavior in the trimix. i'm confused...

some of my buddies channels have the meter drivers replaced with a DIP8 chip, i can look into the mods and let you know how to retrofit if you want. unfortunately all of the channels i have here are stock, but i can get a modded one in a few days time.

I suspect that the problem lies on the channel strip somewhere. For the signal to appear on adjacent channels, it must be hitting a buss somewhere surely ??

I have series 1 & 2 channels in my trimix, both working happily together.

Would be interested to see the DIP chip mod.. I was looking at a Sanyo chip, but the scaling wasn't quite right.

alright....i've tracked down the problem i think. my buddy gave me two different types of submaster modules. two have numbers screened on them..."5" and "6" on one and "7" and "8" on the other. the other two buss modules do not have the screening and i believe that they're originally from his 70 and not from the trimix (they're supposed to be the same thing...). if the signal is bussed to either of the un-numbered strips, the signal appears on all channels meters, otherwise it works fine. I stopped by his studio today and picked up submasters "1+2" and "3+4" and they work fine! no meter bleed if the signal is bussed to groups 1-8. he says they all work fine in his 70.

BUT...

the master "remix" module is a modded submaster module, and if signal is bussed to the master buss the same problem occurs. the only difference i can find between the modules are r62-65, which are marked on the schematic as "A.O.T." not sure what that means??? the 8 working buss modules all have the same values for these positions, but the modded master and the non working submasters are different. So hopefully i can swap those out and the master will work.....but what does A.O.T. mean??


and i have a channel with the chip mod here. i'll figure it out for you the next chance i get.

there's a wee chance these guys have it - they list it among a lot of other obsolete consumer-gear-repair-chips from 70-80'es.

http://www.trelektronik.com.mk/

In Macedonia - so there's a chance it hasn't dried out yet. Judging from the webpage-design, you better call them on the telephone - they probably do not read emails..

Anyways, this is the type of shop where you could have a chance
:razz:

Jakob E.

Baltimore

I can't help you with the remix & subgroup modules. My desk just has matrix modules & the aux module. I made the upper faders 1 & 2 feed the auxiliary channel for master left & right. The next thing I was looking at was converting the last 6 matrix channels to be extra inputs. since that point I got turfed out of my studio & the desk is in pieces stored away :-(

WOuld be grateful if you could post the meter stuff. The Sanyo chip I ws looking at meant reorientating the led's, although I guess in the the grand scheme of things that 's not too big a hardship.

Did you see this trimix on ebay
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=280269263077

Mine is a similar configuration without the mods & but I have 39 input channels !!! I think he's being rather optomistic with the price, but good luck to him !!

hey rob, yeah I saw that trimix. The guy is definitely a little crazy with the price. I've seen 70s in nice shape for $7 or $8000. Certainly a bargain for a console considering the price of the 80s. And why would you mod it to disable the mic pres??? That's half of the charm in these desks.

I'll be able to get to the meter mode this week hopefully. This is the tail end of my slow season in the studio, I won't be busy for another week or two.

[quote author="Rob Flinn"]Baltimore

I can't help you with the remix & subgroup modules. My desk just has matrix modules & the aux module. I made the upper faders 1 & 2 feed the auxiliary channel for master left & right. The next thing I was looking at was converting the last 6 matrix channels to be extra inputs. since that point I got turfed out of my studio & the desk is in pieces stored away :-(

WOuld be grateful if you could post the meter stuff. The Sanyo chip I ws looking at meant reorientating the led's, although I guess in the the grand scheme of things that 's not too big a hardship.

Did you see this trimix on ebay
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=280269263077

Mine is a similar configuration without the mods & but I have 39 input channels !!! I think he's being rather optomistic with the price, but good luck to him !![/quote]

This is wild... The history of the Trimix he posted was from a my post on gearslutz back in Oct. of 2005.

I have not been on here in a while and just saw this and checked out that ebay auction, wild.

A.O.T = Any Operational Tolerance

I'd love to find those Sanyo chips or a replacement for a rainy day.

I could use a couple of these meter driver chips for my TSM also.

:sad:

Bill @ tryaudio doesn't carry them either

[quote author="Baltimore"]alright....i've tracked down the problem i think. my buddy gave me two different types of submaster modules. two have numbers screened on them..."5" and "6" on one and "7" and "8" on the other. the other two buss modules do not have the screening and i believe that they're originally from his 70 and not from the trimix (they're supposed to be the same thing...). if the signal is bussed to either of the un-numbered strips, the signal appears on all channels meters, otherwise it works fine. I stopped by his studio today and picked up submasters "1+2" and "3+4" and they work fine! no meter bleed if the signal is bussed to groups 1-8. he says they all work fine in his 70.

BUT...

the master "remix" module is a modded submaster module, and if signal is bussed to the master buss the same problem occurs. the only difference i can find between the modules are r62-65, which are marked on the schematic as "A.O.T." not sure what that means??? the 8 working buss modules all have the same values for these positions, but the modded master and the non working submasters are different. So hopefully i can swap those out and the master will work.....but what does A.O.T. mean??


and i have a channel with the chip mod here. i'll figure it out for you the next chance i get.[/quote]

Part of the problem maybe that stock Series 70 and Trimix aren't the same animal.
Series 60 and Trimix were much more compatible.
I had a Trimix for 15+ years, technically I am still the owner,
but now it's in hands so large I can't pry it loose intercontinentally.
Domage.

   

Quick

http://cgi.ebay.com/Lot-4-pieces-NOS-unused-SN16880N-IC-for-Trident-console_W0QQitemZ220339677513QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116

noulou said:

   

Quick

http://cgi.ebay.com/Lot-4-pieces-NOS-unused-SN16880N-IC-for-Trident-console_W0QQitemZ220339677513QQcmdZViewItemQQptZLH_DefaultDomain_0?_trksid=p3286.m20.l1116

Click to expand...

Yup I saw this a few weeks back, & I've bought some replacements plus a few spares already !!!!