Serge First Aid

This post will cover some of the multitude of electric and mechanical components that an owner ought to have on hand if they ever plan to DIY a repair.

I haven’t been able to confirm that every one of these is correct or current but the list comes from people who have more intimate knowledge of the STS Serge and Tcherepnin circuits.

Finally, it would be wise to contact Rex first before attempting any troubleshooting or repairs. In the past he has been exceedingly generous with advice, information, and even parts.

So, let’s get to the specifics.


LM3900N – Used in NTO, DTG, TWS, WMX and many older modules
CA3080AE – Used in PCO, NTO, WMX, SSG and old filters and VCAs.
CA3280AE – Used in ACPR, UAP, 2VCA, RING, QUO, WAD.
CA3046 – Used in NTO, PCO, WAD, PRNV, PHA and old UPAP & NEG.
CA3096 – Used in 2VCA, PRNV
LM711(?) – Used in NTO/PCO


There were some secondary sources of some of the ICs. For example, an LM3080 is a National Semiconductor version of the Intersil CA3080.  Same for the LM3046, which was made by several other companies. Only Intersil made the 3280, and they’re gone.

Here’s a resource for ordering some of these:

The common opamps in Serges are still available at the moment:

LM324N – CV opamp
LF353 – FET opamp
NJM4559D – audio opamp
NE5532 – audio opamp
741 – opamp (NTO, SSG)

All of these are inexpensive.  Make absolutely certain sure you get the DIL versions.

NP4250s and 2N5089s are the common PNP and NPN.


From what I’ve read, most faults on Serges are down to wires and pots.

Pots are 16mm Alpha.  50K lin for CV and 50K log for audio.

STS use Mogami for all internal cabling, Rex tells me.

Banana jacks are E.F. Johnson, as far as I know, and all 3.5mm and 1/4″ jacks are Switchcraft.

Last but not least, keep an eye out for the Reticon SAD 1024 BBD which is a critical component in the WAD and very difficult to obtain, and the Phasers (PHA and 2PHA) contain VACTEC Vactrols but I’m not sure what the part number is.

This list is by no means exhaustive and there may be and probably are some inaccuracies. Some of these components may have been updated or replaced with the M-odules but I have seen a large number of these components in my own Oakland and Hartland panels.

serge 009

diy, parts, repair

  1. #1 by b3nsf on July 15th, 2009

    hey matt,

    I’m curious about the little white vinyl stand-offs for the LED’s … I’ve never seen them on any serge panels before, was this stock or modded… sorry for pestering!!

  2. #2 by cebec on July 15th, 2009

    Oh, good question. It’s ’stock’ but on a custom Oakland panel I purchased secondhand. Perhaps those holes were drilled for jacks by mistake. I had to add a stand-off for a jack-to-switch modification on one of my DTGs so that’s how I know they’re sometimes used for this purpose.
    Also, I’ve never seen another 2RVG in pics or in person so it could be something specific to this module.

  3. #3 by b3nsf on July 15th, 2009

    oh man, that just leads to more pesty questions, specifically how you keep getting custom panels even in this modern day M-odules and stock full panels, not that I want anything but what Rex has planned for me (wink wink) but you seem to have found a fountain of youth!! god bless you, sir! keep at it!!

  4. #4 by hexenduction on July 15th, 2009

    Woah. This is a really informative and cool post!
    And the potential for evil is great.
    I’m going to go ahead and buy all those op-amps and create an imbalance on the supply. Then we’ll see what those panels are really worth to you guys. Muwahahahahaha.

  5. #5 by cebec on July 15th, 2009

    b3nsf :

    … a fountain of youth!!

    Haha! More like the ‘Isle of Man’ I acquired custom panel 1 from there + the Animal. The other two came from Hartland soon after and I ordered the second of those when Rex announced ‘last call’ for custom panels.
    Custom panels do come up from time to time, like the one on eBay right now. They are usually a good value if they’re STS. I’d like some older panels some day… maybe…

  6. #6 by pickleinn on July 15th, 2009

    great info – its also nice to know that i have a few of these parts laying around.

    but i feel the more vulnerable parts would be the jacks, pots and wiring…….hopefully it takes alot to damage some ic’s – other than static or hitting the ic with loads of voltage, what can go wrong? i ask because i have no vintage electronics around that have failed.

  7. #7 by Bartlebooth on July 15th, 2009

    Thanks alot for posting may really come in handy someday

  8. #8 by cebec on July 16th, 2009

    You’re welcome. Yeah, I agree — pots, jacks and wires are about all that will likely fail from normal use. The other stuff will hopefully outlast us all.

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