Cgs synth

Hi Ken and all fellow CGS/Serge builders ,

I've literally been trying to get the Stepped part of the SSG , in my VV1 Serge Panel (dmitri panel #1) , going for more than a month to no avail. It's become all i do when i get up in the morning , every day. I'm becoming burned out.

I feel bad asking so many questions but i have very little actual electronics knowledge ; so i have to.

I don't want to lump this all on Ken , so if anyone else can help that would be awesome.

The other day i tried desoldering the join between the L and S pads and it burned the 100n Cap connected to the CA3080.

Can anyone tell me why this would have happened ? It might help me figure out what is going on here.

I'm going mad in a cycle of trying to fix this thing not knowing if the first time i turn it on another CA3080 will be fried or something ; i've socket the J201 and reversed BC557 for now , CA3080 , LM3900 and TL072 are all socketed.

8 pin sockets are machined , 14 pin are not.

As Neil said pictures would definitely help. Looking at the data sheets the BC557 should be reversed as the pinouts are the other way about to the PN4250.

The issue with the 100n is strange but they are close on the board and also to the BC557 - did you initially have the BC557 the other way round and have to desolder it? Is it possible there's been some damage to the board in that area?

Also have you tried adjusting the trimmer? I built a DUSG this week and was getting nowhere with it until I tried that - sometimes it's not a setting to taste, you need it in the right place for it to work at all.

I'll try and get some photos up.

I have desoldered a few components a few times the reversed BC557 and the J201 and a few wires.y wiring is a bit hackneyed as I use a larger gauge wire than the anchor holes allow but it's never really caused me grief and I've built 6 of these panels in the last 3 years and i'm onto 7th.

The full SSG I built in Dmitri panel #2 works no problem.

I had a similar situation as this on my first panel with a CGS29 Wave Mult. Ended up swapping it out for a Serge Wave Mult.

I'll try the trimmer again too.

Thanks , I'll keep you all posted.

On 09/11/2013, at 8:51 PM, Scott Young <thebot@...> wrote:

As Neil said pictures would definitely help. Looking at the data sheets the BC557 should be reversed as the pinouts are the other way about to the PN4250.

The issue with the 100n is strange but they are close on the board and also to the BC557 - did you initially have the BC557 the other way round and have to desolder it? Is it possible there's been some damage to the board in that area?

Also have you tried adjusting the trimmer? I built a DUSG this week and was getting nowhere with it until I tried that - sometimes it's not a setting to taste, you need it in the right place for it to work at all.

From the photos it looks okay to me. It's hard to tell on the track side for obvious reasons. Have you tried to simply get it to work as a Smooth, by leaving out the link between L and S?

From the photos it looks okay to me. It's hard to tell on the track side for obvious reasons. Have you tried to simply get it to work as a Smooth, by leaving out the link between L and S?

---In cgs_synth@yahoogroups.com, <okayjustalittle@...> wrote:

Photos are up !

On 09/11/2013, at 9:28 PM, Stephen Richards <okayjustalittle@...> wrote:

I'll try and get some photos up.

I have desoldered a few components a few times the reversed BC557 and the J201 and a few wires.y wiring is a bit hackneyed as I use a larger gauge wire than the anchor holes allow but it's never really caused me grief and I've built 6 of these panels in the last 3 years and i'm onto 7th.

The full SSG I built in Dmitri panel #2 works no problem.

I had a similar situation as this on my first panel with a CGS29 Wave Mult. Ended up swapping it out for a Serge Wave Mult.

I'll try the trimmer again too.

Thanks , I'll keep you all posted.

Only thing that I can see from the photos is a bit of discolouration around the 220n next to the PN4250 / CA3080. Probably nothing but would be worth checking for continuity on the parts round there. It's nice tidy work so the only thing I can see being an issue is where you've had to desolder.

Cheers,
Scott.