The Fun Never Ends With My 388 Misadventures

  • Thread starter Thread starter Mark7
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If I can't get the in built mixer working again I'll just save up and buy a new mixer.
 
Mark7 said:
Can I delete this thread?
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I don’t think you have control to do that, but you can always ask a forum moderator to delete it. Anybody know for sure?

I’m kind of hoping not, because there’s valuable information in here about how to prepare before taking things apart with units like the 388, and some steps to take if you don’t prepare…how to logistically dig out. Also, my opinion, but I think it might be worthwhile for others to have some sense of what they might be getting into if they decide to assist you.
 
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sweetbeats said:
I don’t think you have control to do that, but you can always ask a forum moderator to delete it. Anybody know for sure?

I’m kind of hoping not, because there’s valuable information in here about how to prepare before taking things apart with units like the 388, and some steps to take if you don’t prepare…how to logistically dig out. Also, my opinion, but I think it might be worthwhile for others to have some sense of what they might be getting into if they decide to assist you.
Click to expand...
Just wanted to say you’re an absolute saint for hanging in this long!
 
Don't care. I'll just wait until I can pay someone to reconnect the wires for me.
 
It's not the connections. I hooked the rest up as best I could using wire length and logic and it's still exhibiting the same behaviour. Unless the switching logic is on one of the connectors we didn't get to it can't be any of them.

I think the m,buss board is to blame somehow, but the only possible cause are a couple of possibly cold solder spots on the plus and minus 15v tracks at the connection to the A buss board, and I can't see what those have to do with where a signal is bussed.

Yes, we call them boards over here. It's less syllables than PCB, We're lazy.
 
I realise no one cares any more, but here's where I am so far.

The stereo buss is fine. The L/R buss is unresponsive.
 
The sockets for the LED are two conductor Molex connectors which I am not sure you can still get them. I bough a bunch for the card edges of 38 and so on as when the hook breaks the cards will not plug in correctly. That is usually done by amateurs jamming the cards in any old way. Bulls in a China Shop.
 
Update. Turns out you can still get two conductor Molex connectors

IMG0155A.webp
 
Got the molex connectors soldered in by a pro and the board is back home and in its rightful place. Fell into place perfectly with no jiggling.

Now I just need to get the pot for Monitor 1 gain sorted. Remind me, is it linear taper or audio?364231942_993370555197880_473874671421203892_n.webp
 
It is likely an audio taper pot. I can’t remember if your monitor 1 gain pot is missing or just damaged, but the specs for the pot are printed on the pot body…if your monitor 1 pot is missing altogether just look at what’s printed on the monitor 2~8 bodies. It’ll be something like “10KA” or something like that which means 10KOhm and “A” taper which is “audio” taper.

You can post what’s marked on the pot or look in the parts list in the service manual at how it’s described and post here for decoding.
 
It's a 10KA pot, according to the manual, with a 15 to 16mm shaft (no, it's not missing),

Also according to the service manual it's 1S1UVR 16, 10KA.
 
The problem that seems to have developed in that particular pot is thus. Turning it has no effect until around three quarters of the way through its travel. Then there's an audible click (and you can feel it as well) and then it starts working, but the sound is terrible. It's the original part, so it's not been accidentally replaced.
 
10KOhm audio taper pot then, and sounds like it needs replaced.
 
Bugger. Those things are impossible to find with that shaft length
 
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