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solewheelin
Bronze Member
USA
53 Posts |
 Posted - 04/03/2009 : 08:45:02
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I have always wanted a CS1 and I bought one recently in non functioning condition.
Its in pretty rough shape, but for 20$, I decided to chance it.
When powered with my DC Brick, the pedal LED lights up but there's no sound.
Any idea what steps I can take to figure out why this pedal is malfunctioning? The bypass works, but not the effect.
I assume its something simple, and I have a multimeter that I STILL don't know how to use.
thanks for any advice |
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IM28
Copper Member
26 Posts |
Posted - 04/10/2009 : 16:08:49
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quote:
Originally posted by solewheelin
I have always wanted a CS1 and I bought one recently in non functioning condition.
Its in pretty rough shape, but for 20$, I decided to chance it.
When powered with my DC Brick, the pedal LED lights up but there's no sound.
Any idea what steps I can take to figure out why this pedal is malfunctioning? The bypass works, but not the effect.
I assume its something simple, and I have a multimeter that I STILL don't know how to use.
thanks for any advice
Some basic trouble shooting steps:
1. Try the effect with a known good 9V battery
2. Open the pedal and do a close visual inspection for any broken or loose wire connections. Inspect the printed circuit board for any burnt or broken components.
3.Inspect the solder side of the printed circuit board for bad or cracked solder joints. Good joints are smooth, shiny and not lumpy or rough looking. You may want to use a magnifying glass or loupe to really see any problems. If you suspect a bad joint, reflow the joint with a soldering iron and some fresh solder.
4. Give the pots a shot of contact cleaner and check that all hardware is tight(This is just basic maintenance and I do this as a matter of routine on all trouble shooting of pedals amps etc.).
5. If you have the schematic and are able to read it you can start tracing the signal through the pedal. You will need a signal source like an ipod or cd player to connect to the pedal input and an basic audio probe which you can easily construct http://www.diystompboxes.com/pedals/debug.html
You really need to be able to read the schematic to do a good job of tracing the signal. You should start at the output of the pedal and work your way back through the signal path.
5.Post your findings or pic here on the forum and we will follow up with more advice |
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verivorax
Platinum Member
Canada
1185 Posts |
Posted - 04/10/2009 : 19:57:10
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Definitely try the battery first.. my guess is that it's just looking for 12v unregulated (ACA), and the DCbrick is providing 9v regulated (PSA).
Good luck! even if it never works.. $20 is a great deal for a CS-1! (What's the serial? can we see pics? silver screw?) |
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solewheelin
Bronze Member
USA
53 Posts |
Posted - 04/17/2009 : 08:40:07
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Thanks for the replies.
Here are some pics.
It looks like a big chip could be missing from the board.
The circuit board also looks a bit white in some spots around the solder joints.
What do you guys think?
Serial# 0400
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 04/17/2009 : 10:01:43
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The missing chip is a TA7136P - make a note of that campers, it's not marked on the schematic and I had to take my CS-1 apart to find out what it was.
You can buy one here: http://www.smallbearelec.com/Detail.bok?no=579
Everything else looks OK... BUT... the IC was taken out for a reason. Perhaps some other part of this pedal is broken and it was used as a donor. No way to tell until you replace the IC and give it a go. |
Edited by - Laurie on 04/17/2009 10:02:37 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/17/2009 : 18:11:55
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Hi solewheelin
for a $20 - I would pend the extra few $$$ & get the TA7136P from SmallBear, as Laurie has pointed out.
Someone may have needed it for a repair project on a synth or another more expensive compressor?
The Rest of the PCB & components look good.
While you're at it, buy some replacement knobs, & I belive you will have yourself a nice CS-1.
Let us know if you need anymore help, when you get the TA7136P.
If you're not too sure about soldering & stuff, ask a friend who has worked on some electronics & PCB's to help you out.
Congrats again.
Regards Dr. Bob 
PS
stupid thought for the day,
ask the seller if he still has the chip?
You never know?
Regards again Dr. Bob
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Edited by - Dr. Bob on 04/17/2009 18:13:21 |
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solewheelin
Bronze Member
USA
53 Posts |
Posted - 04/18/2009 : 00:58:42
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Wow, thanks so much. That was some great advice.
I can handle soldering, yes, and its worth it to get it going.
Ill order it from small bear, get to work and report back.
Ill also ask the seller if he still has the chip.
Thanks a lot!
edit - The TA7136P is 2.00 and not $20 like Dr. Bob said :)
Heres some more discussion on it.
http://www.diyaudio.com/forums/showthread.php?postid=523251
Maybe I can find the chip in an old broken receiver? |
Edited by - solewheelin on 04/18/2009 01:06:58 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 04/18/2009 : 03:38:26
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Hi solewheelin
quote:
edit - The TA7136P is 2.00 and not $20 like Dr. Bob said :)
I guess it was really late (2:15AM) when I wrote that  ,
What I really wanted to say,
was that the CS-1 was an absolute bargain for the $20, that you paid.
FYI & others:
The HTV P873A, black tubular components, are the twin LED optocouplers.
Did I see a SS in one of those pictures?
What is the serial number?
Regards Dr. Bob
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solewheelin
Bronze Member
USA
53 Posts |
Posted - 04/18/2009 : 10:51:01
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Yes, I have been watching them for a while and while they go for $60-70 in decent working condition. 20$ is good for one that powers up but only seems to be missing a cheap missing part. I was told not many pedals used the T7136P in their circuitry and that it was used in older stereo receivers. Im just glad its not some rare chip I need to find.
I always wanted a CS1. I had many CS3s old and new, a 1st month 1981 CS2, a few stock/modded Dyna Comps, A CP10 and now this.
If im not pleased with the sound, I am going to give the Monte Allums opto-mod CS3 a shot. I see them go for pretty cheap as well.
Thanks again
BTW it is indeed a silver screw, and the serial # is 0400 |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 04/18/2009 : 15:56:42
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G'day solewheelin! We've been discussing the CS-3 off and on here ever since I've been a member (and before). The emerging trend is that the early CS-3's that have "dBX" brand VCAs sound good. The later ones that use "THAT" brand VCAs not so good.
I have a late model THAT CS-3 with the opto-plus mod plus a bunch of other tweaking, and after hours of work it sounds "OK to my ear". Compare that to my MIJ dBX CS-3 that sounds superb out-of-the-box. Could be just my ears but it seems real.
PS: if you are going to order that chip from Small Bear, they also have replacement knobs that are close to the originals:
http://www.smallbearelec.com/Detail.bok?no=105 |
Edited by - Laurie on 04/18/2009 16:42:26 |
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solewheelin
Bronze Member
USA
53 Posts |
Posted - 04/21/2009 : 05:23:04
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http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=300307259328
This is interesting.
Boss apparently used the same serial numbers on their older pedals?
This one in mint condition has the same serial number as mine.
Weird. Anyone ever see this before?
Again thanks Laurie and Dr. Bob for all of your help.
BTW Laurie, my older CS3 did seem to sound a bit better than others I had but I never checked the VSAs. Oh well, I have a feeling I am going to like the squish of the CS1.
Cheers! |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 04/21/2009 : 21:02:49
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Yes, the early numbers were, I think, "month" numbers - someone who has more knowledge than me feel to chime in.
Anyway, there are batches of the early pedals all with the same serial number.
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CS1 Fix?
