Build Your Own Clone Message Board

I'm in the middle of gutting an old but beloved 4-track Tascam reel-to-reel. (sorry about that, but the motor died, and I felt it was time to scavenge).

So far I've removed the tape controls rack, and there are thirty 14-pin ICs inside, all in sockets. The first one I randomly punched into ebay turned up some going for $8-10 each , so I thought I'd put some part #'s up to see if anyone recognizes them:

HD4123P
HD7400P
HD7402P
HD7408P
HD7404P
HD7410P
HD7414P
HD7438P
HD7451P
SN7412N

I thought maybe Insonicbloom might spot something familiar? If not, I'll start poking around for datasheets..

The next rack to check out is a four channel dbx dolby add-on rack underneath the control panel.. looks like a lot more socketed ICs in there too..

Looks like a bunch of logic chips (NAND gates, mostly). And a hex schimtt trigger inverter (7414).

You might be able to make some kind of wacky dirt circuit with that 7414. I'd set it up like a Tube Sound Fuzz and see if it makes noise.

okay now I've cracked open the DBX noise supression unit, and I've uncovered sixteen JRC 4558DF chips, and a handful of JRC 4558DD's, all circa 1982 or so.. Is this mojo enough for me to spend the time desoldering? Is DF or DD any kind of monkey wrench here, or just a tacked on manufacturing suffix?

30 years old sounds like mojo to me.......

HD4123P - dual retriggerable monostable multivibrators with CLR
HD7400P - quad nand gate
HD7402P - quad 2-input P NOR gates
HD7408P - quad 2-input P AND gates
HD7404P - hex inverters
HD7410P - triple 3-input P NAND gates
HD7414P - hex schmitt trigger inverters
HD7438P - quad 2-input P NAND Buffers with open collector outputs
HD7451P - AND-OR-Invert gates
SN7412N - triple 3-input P NAND gates with open collector outputs

I thought maybe Insonicbloom might spot something familiar? yes, I use all of those or variations quite often - pretty tedious typing all that out though!

if those logic (TTL) ICs are soldered onto the board I would invest in one of these solderers clip heatsinks
http://compare.ebay.co.uk/like/13059498 ... sbar&cbt=y

then you can rescue all that bullcrap "mojo" op-amp stuff you want
haha

I've got big draw units just for Logic ICs they are so useful so I would definitely get them off
it might be a bit difficult to locate datasheets for those ones because HD (hitachi) took a lot of liberties with component identification

A man after my own heart! The "mojo" is in the player, not the equipment.

I love mojo stuff especially if it looks different. Has nothing to do with any perceived effect on sound - I just like the thrill of the chase and the boost to the gut shots!

oh I can fully agree with that, often if I know the board is going to be on show in something, I will load it up with can op-amps, tropical caps and allen bradley resistors. then because those things are notoriously temperamental I'll seal it in clear resin so temperature can't get to it easily!

when using old resistors I double the value needed and put 2 in parallel so they are more stable eg if I needed 33k I would use 3 100k in parallel
you can get some pretty impressive looking boards that way with little resistor log-cabins populating the thing!

^triple the mojo!