Is there any way to test 3207 and 3102 BBD chips?

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
Post Reply
User avatar
Rambozo96
Breadboard Brother
Information
Posts: 51
Joined: 07 Oct 2018, 23:01
Completed builds: Superfuzz’s, Mosrite Fuzzrite, various Tonebenders, some oddball Russian stuff, MXR Distortion II, modded various DOD pedals to true bypass, opamp Big Muff.
Has thanked: 10 times
Been thanked: 40 times

Post by Rambozo96 »

I recently got a newer Arion Stereo Chorus that only outputs a clean sound when engaged and I don’t want to just shotgun parts into it hoping it works. I would guess maybe the first culprit would be one of the BBD chips but I’d like to know if there was a way to test them to make sure.
Attachments
4E5B8261-6783-4447-BC09-84BDAACDE544.gif

User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

I recently had 2 (identical) choruses in to repair (Identical schematic to the Behringer UC100), one had bad noise on the chorus signal, the other only had clean output.

I downloaded the datasheet for the 3207 and 3102 and found that on the second one there was no output from the 3102 (pins 7 & 8) so I robbed the chip out of the noisy one and got one working.

The first one was noisy even without the 3102. I tacked this down to a surface mount transistor, it was either a bad joint or a noisy transistor. I swapped it and that cleared the noise. I then ordered a 3207 and 3102 pair from China (dirt cheap), replacing the 3102 restored the chorus signal.

Total cost 0.99 GBP and one transistor pulled from a random scrap board.
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

deltafred wrote:(pins 7 & 8)
That should read pins 7 & 8. 8 followed by a closing round bracket must be the code for a smilie!
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

User avatar
Dirk_Hendrik
Old Solderhand
Information
Posts: 4193
Joined: 03 Jul 2007, 08:44
Location: Old Amsterdam
Has thanked: 232 times
Been thanked: 887 times
Contact:

Post by Dirk_Hendrik »

deltafred wrote:I. I then ordered a 3207 and 3102 pair from China (dirt cheap),
So did I years ago! They looked fine I thought.... but got very hot once powered. I learned a lot about Chinese fakes since that time. And, over the years I more and more get amazed that the attitude of absolutely not caring about selling fake stuff, reworked stuff and all other forms of fraud is so common in China.
Sorry. Plain out of planes.

http://www.dirk-hendrik.com

User avatar
deltafred
Opamp Operator
Information
Posts: 1654
Joined: 06 Apr 2010, 16:16
Location: England
Has thanked: 813 times
Been thanked: 306 times

Post by deltafred »

Dirk_Hendrik wrote:So did I years ago! They looked fine I thought.... but got very hot once powered. I learned a lot about Chinese fakes since that time. And, over the years I more and more get amazed that the attitude of absolutely not caring about selling fake stuff, reworked stuff and all other forms of fraud is so common in China.
I got mine in August 2018, I only used the 3102 and it worked fine so guess I was lucky.

I did think at the time that I might be wasting 0.99GBP but figured it was worth the risk! :lol:
Politics is the art of so plucking the goose as to obtain the most feathers with the least squawking. - R.G. 2011
Jeez, she's an ugly bastard, she makes my socks hurt. I hope it's no ones missus here. - Ice-9 2012

Post Reply