Avalon vt-737sp
- Thread starter Jdm5149
- Start date
Help Support GroupDIY Audio Forum:
Hey there. Big news. Got a ssl4000e. It’s in not that good condition but I think it’s gonna be a great board again once I finish. Should I start a new thread or are there other threads open that could help. I want to start with the channels and was wondering if it is possible to test them disconnected from board? Im selling off things to pay for the board but the Avalon 737 is not one of them. Definitely a keeper.
pucho812
Well-known member
Congrats on the new desk. I hope it came with the manuals. I also hope you have the program disk or can do the vca fader bypass so the desks works.
Thanks. I was gonna wait til I moved but the deal was I hope too good to pass up. Got all the disks but no computer. Just power supply Eventually a tangerine I just want to start working on channels by themselves. The desk will be in storage. Can I make a test jig for the channels. I see a 4000 extender on eBay. Should I get it
chrispbass
Well-known member
Best to start a new thread
deveng
Well-known member
I've acquired all the replacement parts for the I/O board but found some burned trances below Q9 that halted my rebuild. The top side is burned deep so I'll have to rebuild some connections. The bottom side is burned as well but looks like all the traces are there.. I've attached some pictures of the area. Can someone tell me if the traces I've marked are correct? I've also attached what looks to be the connections to Q9 (BD140). The circuit diagram just shows the trace connections in question. There are other wired connections but those trace are all intact so I'm not concerned about those. If anyone has close-up pictures of their board showing these connections that would help too.
pucho812
Well-known member
Can get you photos when I get in
pucho812
Well-known member
@deveng
Hope this helps. if you need more photos beyond this, let me know.Might I suggest the following as well. As part of the repair process, replace all the 10UF and 100UF caps. They should be 63VDC nd 50VDC respectively. I use Panasonics as I don't care for the caps they used in the builds.
Hope this helps. if you need more photos beyond this, let me know.Might I suggest the following as well. As part of the repair process, replace all the 10UF and 100UF caps. They should be 63VDC nd 50VDC respectively. I use Panasonics as I don't care for the caps they used in the builds.
Attachments
deveng
Well-known member
Thanks pucho. I found that photo already and it doesn't show enough detail around/under Q9 transistor on the top layer. I think I need a close-up of the area around Q9 if anyone has one or can take one easily.
deveng
Well-known member
I think those are great, thanks for your efforts!
TheseGoToEleven
Well-known member
- Joined
- Sep 4, 2020
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Another gut shot of the I/O board if it helps
deveng
Well-known member
Repaired the burnt traces, replaced BD140 BD139 pair and replaced all electrolytics. The board does work now but I found at least one bad 6922 tube. According to Avalon and their replacement set at Sweetwater, they have a set of 4 matched EH6922's. I can't see why these tubes require matching unless they are matching the two sections in each tube? Is that really necessary? Any suggestions on replacements, EH, JJ etc? The originals are Sovtek
deveng
Well-known member
Forgot to mention, the preamp gain pot is starting to go bad. I think something related to the center detent. The resistive sections seem to work ok but when rotating the shaft feels rough and grinding especially near the center detent area. Its obviously a custom part. Looks like a Clarostat dual 25k with center detent.
Part number is C0104199. Studio Electronics Burbank has a 50k dual not sure if that's an acceptable replacement for this unit??
Part number is C0104199. Studio Electronics Burbank has a 50k dual not sure if that's an acceptable replacement for this unit??
Glad u got it going. I basically rebuilt the power supply and replaced a lot of pots and the vu meter. Mine was really *******ized. I did replace the tubes with the ones from Avalon. I still have the old ones but have to see if they were originals. Still in process of moving so once I finished it I put it in storage. Can’t wait to setup everything again. I did use the preamp gain from those guys. One thing I noticed was the knob didn’t have the center detent like the others. But otherwise worked.
The center detent on the gain pot wouldn’t be missed. Output pot, maybe.
I replace tubes only as needed, not 4 at a time. Just get tubes from a reputable source. If you buy a set from sweetwater, you’ll have spares for a few years. Tubes in our units ( powered on 40+hours per week) still last a couple years.
I replace tubes only as needed, not 4 at a time. Just get tubes from a reputable source. If you buy a set from sweetwater, you’ll have spares for a few years. Tubes in our units ( powered on 40+hours per week) still last a couple years.
