Help, Identify Circuit Board.

[Lonestarjohnny]

I have a C/B that I found in some stuff I bought at a sale and I wonder if anyone can help identify what it was made for, The board is 4x5 in. in size, it's marked on back EH 131, and came with a bag of parts that I can see go to this board, some of the parts are 1- RC 4558NB, 1-UA741, 1- LM 381N,1-F 7734, 1-BC309, 1-7712, 5- Trimmer pot's and some caps, resistor's, and diode's,
I assume this was made for some sort of a Electroharmx pedal but wish I knew which one.
Thanks
JD

[petemoore]

Quite a Find !!!
 Did you try wiring it up yet???

[Lonestarjohnny]

No I have'nt Pete, It's still all bagged up in piece's, I have'nt the slightest where all the parts go on the board, thats why I'm trying to find out what it is, then maybe I might find the schematic to wire it all up and try to see if it would work,
JD

[petemoore]

Bare Board...Hmmm...uh...I guess that's why you're trying to go by the #'s on it....
 If it's possible to get PICs up of it, we could pass them around and see if anyone recognizes that guy.
 Sorry I can't be of help, I thought it was a populated board...You can tell where the Dual and single Op amps go by the V+ connections...dual would be pin 8 single is pin 7...
 Hopefully someone can recognize the parts combination.

[phillip]

Hmm, here's some info from the EH Man's website.  These are some EH numbers that have "EH 131" in them.

EH-1311      Echoflanger
EH-1313      Mike Matthews Dirt Road Special amplifier w/phase shifter
EH-1314      Talking Pedal speech synthesizer
EH-1315      Slapback Echo
EH-1316      Soul Preacher compressor/sustainer
EH-1317      Clone Theory
EH-1318      Deluxe Electric Mistress flanger (circa 1978)

Dunno if it's any of these, but they're the only ones that had "EH 131" in the part number.

Phillip

[Peter Snowberg]

If I had to guess from that list I would probably go with the Soul Preacher. I don't recognize the 7734 or the 7712 chips. Hmmm.....

[Lonestarjohnny]

Thanks Phillip,Pete, Your right about the #'s, I shoulda cleaned the board better before posting, the last digit had a piece of pricetag covering the last no. , it's a Era 1978 Mistress Flanger board, never been used, EH 1318, now to find the schematic and populate the board to see if we got us an old Flanger,
Thank's Guy's,
JD

[Marcos - Munky]

I have a schematic dated 1977, one dated 1980, one dated 1981 and one without date. E-mail me for them.

[Lonestarjohnny]

Peter, Much to my Displeasure, S/S device's are not my Expertese, though I am enjoying learning to build my own pedal's, Some of the larger chip's have 2 no's on them and me being on the Dummyhead side about said device's, I probably gave the wrong #'s,  :oops: ,
Thank's
JD

[Peter Snowberg]

OK... that makes total sense. The 7734 and 7712 are date codes for the manufacture of the chips. It's a fairly standard industry numbering system with the first two digits being the year and the last two being the week of production. (you'll also find similar codes on pots and some [usually older] caps)

Sometimes finding the right numbers on unfamilliar parts can be easier said than done.

Congrats on your "new" flanger!!!!

I'm guessing that one of those chips is a BBD. Maybe a SAD1024 from Reticon? If you have the BBD, you're half of the way home.

Take care,
-Peter

[phillip]

Wow a Deluxe Electric Mistress...you got lucky!  Wish I could find something like that sometime

Phillip

[Lonestarjohnny]

Peter, It's got the Reticon SAD1024A and 2 other 14 legged chips, 1 is a SCL4013 EE I think, it's blurred somewhat and the other is LM324N,
I have Schematics for the #2,3,4, And 5 version's, but this one is very Different than those, They show many opamps, this one does not seem to be one of those, maybe it's older,
Thank's for the Help,
JD

[Peter Snowberg]

Cool!

The 4013 is just a standard 4013 dual-D type flip flop for the BBD clock generator. I'm guessing that the LM324 (quad op-amp maade for single voltage supply) is probably the core of the BBD oscillator and the LFO for sweeping it.

The 324 has 4 opamps, the 4558 is a dual, and the 714 and the 318 are both singles. That makes 8 opamps total.

It sounds like you're in really good shape.

take care,
-Peter

[Lonestarjohnny]

Thanks alot Peter, this came out of big box of busted pedal parts I bought at the Flea/m the other day, I know there are some other delay stuff in the box, maybe some more BBD chip's, I'll post them for trade if I find I have several or more good one's.
JD