I have a Kustom "Frankenstein" style head whic I can't ID.  It does not appear to have any numbers on the PCBs.  It is very bare bones, two channels, Treb, Bass, Volume each channel, six TO-3 RCA transistors on the back labelled 36892. No "200" on the front plate, just "Kustom", but I am assuming that's what it is.  It looks all original, everything coated in a fine layer of grease, it works but has odd intermittent bursts of noise, kind of like an AM radio during a lightning strike, almost like dirty pots but it happens on both channels and is independent if turning any of the controls.  The controls do what they are supposed, volume makes it louder, bass makes it brassier, treble makes it trebly.  I haven't made any measurements yet, because I am hoping you guys might steer me to the closest PCB schematic. I assume there is a lot of similarity in the boards?

Okay, it's not really a guitar amp, it's the power amp for a Kennwood Eleven GX, and it came with dead outputs and a bunch of burnt resistors, and after checking a number of other dead transistors.  Problem is where to find some of these transistors?

Drivers: 2SC1913, 2SA913

Also:  2SA733R (Q), 2SC1735, 2SC1845 (F,E), 2SC945R (Q)

I tried looking at MCM, but did not see any of these guys. 

A lot of the smaller ones are ECB.  I have the feeling there are things that would work with some leg bending.

Any advice on how to pick substitutes?

   

Hello Gurus:

I have a rickenbacker tr-14. The reverb pan is an accutronics 1FC2C1B (9", 2-springs).  One of the springs has detached itself and on one end the small ferrite bead and little attaching wire have gone awol.  Basically, I don't think it's fixable.  Looking around at AES and so forth, I don't see many pans with "FC" specs (1475 ohms input imped, 10,000 ohms out). How critical is it that a replacement pan have exactly the same specs? This is all-transistor amp from 1980's, I think.  I don't have schematic.

 

Okay.  So I have this Earth Sound Research transistor amp.  I got it up and running by replacing all electrolytic caps and the output devices (I used 2n3055 from mouser).   I don't have a schematic, but it looks very similar to peavey pacer in jack darr's book p. 263.

My issue is hum in the reverb section.  Amp is fairly quiet and normal with reverb on 1, if you turn it up to 10, it reverbs, but with hum.  I tried replacing the reverb wires and soldering to the inside of the rca jacks.  This helped a bit.  Oddly, when the pan is not bolted in, with chassis on my bench, it has less hum than when bolted in the amp.  The pan is not in  a bag, but is screwed to the chassis through rubber grommets.  It doesn't touch the chassis, but it is close to the transformer and everything else.  What else should i be thinking about?  I want to sell this amp and I want it to be quieter before i do.

I am looking at a couple of transistors labelled "RCA 7155" that I can't find info about in my (admittedly old RCA manual) nor online.

Anyone have any info on what these are and what they could be replaced with?  It is NPN power transistor, but must be fairly low power, has about 17.5 DC volts from C to E.  They are in a Kalamazoo model 4, for which I don't have a schemo.  I found a Kalamazoo 3 schemo online which listed it as Motorola SJ 3405 or 3408 (I can't read the last digit).

The good news is, these work for now, but I am always curous if I had to replace something what I might use.

Can you guys suggest some replacements for TIS-98, which seem to be hard  to find?

I was looking at PN3568 or BC637 from mouser, they seem to be similar.  Application is Rg-80 Randall.  Collector to Emitter is just over 40V in the circuit.

Hello:  I am new to this group (first post here) and am also owner of a fairly beat-up Randall RG-80 (circa 1983).  I have been working on it (which I detailed on another amp forum so I won't go into it here), but this being a forum dedicated to Solid state I am wondering if there are any fans of the RG 80 here?  By fans I mean that you use one and like it.  I really dig it (despite the hum problem I am working on), the "red" channel is really fun when cranked, it is quite loud for what it is.