Hi Tux.
As a general idea, it should work.
I suggest you start "backwards" and going from the simplest to complex.
That means: get some kind of chassis, a bent piece of  aluminum or equivalente, where you can mount everything.
Start by the TDA2030 amp, build it, hook it to a speaker and your guitar (it will sound, although low volume and *very* clean) .
Then add the channels, one by one, and test them.
I guess adding the MayBooster will be too much, you´ll very probably get crazy with radio, squeals, noise, motorboating, etc.
Good luck and have fun.
Don´t forget to post pictures and MP3s.
JM

It *may* be overheating, with the thermal cutout shutting it off when it senses danger. Does it make any strange sound: whistling, hissing heavily, humming even with al controls off? There are *many* other possibilities too, but start by checking that. Bye.

Dear Jack, I understand fully what you feel. Instrument amps not only get moved a lot , wheeled or not, but they also endure a lot o trips in the back of pickup trucks or regular cars, and even if they "live" in a rehearsal room, the music itself shakes them to death. Boards flex and develop almost invisible cracks, and all heavy components (specially big filter capacitors) eventually get loose. I have even have seen quite a few of them who crack solder and pull themselves from the board and even some &%$*^&%$ of them with pins *internally* cut or broken. On many humming/popping/oscillating/unstable amps I start by soldering a couple of good filter capacitors (even if they have some less capacitance than the original ones) and more often than not the problem is diagnosed in minutes. Really, as you say, that´s the "step one". Bye.

Dear Bugo, you got it quite right, sorry if I wasn´t clear enough, so, as "one image is worth 1000 words) here you get two. #1) is a hand-drawn schematic of my "breadmaker", my P100 module.  I´ve built around 10000 of them, the first 9000 or so with 2N3055H+Tip31/32 drivers, which lately had to be replaced by Tip141/142 because nowadays it´s almost impossible to get a genuine 2N3055H. The current version uses IRFP250 which are close to indestructible.  #2)Is a poor scan of the board "ready-to-mount": : the 100W/4 ohm amp is the center section, on the right is the +-42 power supply, and on the left are the +-15V preamp supply outputs. When I get my camera back I´ll post better pictures.
Dear Teemuk, thanks for clearing Bugo´s doubts.
The amp´s sensitivity is around 700 mV, it has mixed voltage and current            feedback. Power output is 20 clean volts into 4 ohms and supports many "ooops!!! sorry!!!" shorts.
Bye.
JM

Thanks Teemuk, great sites, very useful.  There are zillions of tube amp links out there, but SS are *very* hard to find. Many of them mysteripusly go "off air" without warning. Also found Peavey´s replacemente link very useful.

If they blow or smoke in seconds they´re wired backwards. Since they worked for weeks,I must assume that their voltage rating is marginal at best. Replace them with caps that  support at least 10 volts more than what´s nominally needed and you´ll have no problems. The "100/150" *will work*, but it´s just a regular classic schematic stripped to the bone and then some. You should at least: 1) add a 100pF ceramic cap from Tip41´s base to collector ; 2) add a Zobel network: a .1ceramic in series with 10 ohm 1/2 W resistor, from "hot" output to ground (or across output jack) ; 3)split the 22k resistor into two 10k´s in series and wire a 100uFx35V capacitor from the midpoint to ground ;4) add a third biasing diode in series, the three of them should be epoxied to the heatsink, the amp will still be somewhat underbiased but usable ; 5) definitely not "150W" but will pull around 90W into 8 ohms with the +-45V or, (much safer) into 4 ohms using +-35V. By the way , avoid shorts at all cost  because it has no protection whatsoever.

Great amp, sounds *very* good, don´t understand why they stopped selling it. I guess perhaps it´s "somebody else´s" product, maybe only distributed by SLM.  In that case, if the contract was not very good for the real manufacturer, they might have not renewed it. The product itself is very good. By the way, I´m curious about it, don´t you have the schematic? I wonder about the "Class D" amp. Thanks.

Hi Darwin. Nice preamp, should sound good. Will work better with 12V than with 9V. Please post some MP3´s and pictures when ready. Bye.

Hi Darwin, please post the schematic or link to your preamp. If it´s powered with +12V, just get them from +B (in this case around 24V ) with a resistor (1K 1W), a 12V Zener and a 100uFx16 or 25V electrolytic. Don´t worry about your preamp  asymmetrically loading your supply, it uses nothing (a few mA) compared to the 3886. Bye.

Dear Muttomatic: now I know that the schematic and questions I posted before are useless in this case. My browser only showed me part of the picture you posted, I wrongly assumed that the board (and U shaped heatsink) were *much* longer, possibly containing other two TO3 devices and some other stuff (and a chassis mounted driver transformer). Now I "pulled" the full picture, opened it into Irfanview and sharpened it as much as possible. I´m posting a sketch of what I think the power schematic looks like, you´ll have to correct it and "fill the blanks". I assume the input transistors are NPN and the "Class A" PNP but the reverse is also possible. I´ve also drawn both outputs NPN, but they might be complementary (NPN/PNP). Please redraw the schematic as you see it on the actual board; also a couple more sharper pictures will help a lot. If possible also include a bottom one (solder side).  To begin with, the amp has no short protection at all; not so bad within a combo, but if you add any external speaker, it becomes very dangerous. We still need that Molex drawing and voltages.Still suspect your -B is missing, also +-47V is too much for 2n3055/2955 devices.  Bye.

Dear Yus , thanks for the schematic. Thanks God you could quickly repair it. These HK guys really know their stuff. Relatively simple amps, *very* good sounding ones. I remember a Guitar Player "test/competition": this Attack40 Vs Valvestate 40 and some Fender. Their final answer?: "The attax 40 is the only one *without* tubes (all others were hybrid), yet it´s the one with the "tubiest sound". Enough said!
Thanks again.
JM

Dear Muttomatic: please don´t get desperate and start changing parts at random. I guess you misplaced some of the power diodes at the power supply, that´s why now it blows fuses straight away. Return it to the original state. You need that power supply working before you can proceed with anything else.
I´m posting a refried schematic, the very poor one seen before. We´ll have to use it for now, we have none other. Please do: 1)Label the transistors with their real names. If in doubt, copy every inscription on them, not on the schematic itself (it will get very cluttered) but on the text of your post. Also label them on the board or chassis as "Q5" ... etc. with some Sharpie or Magic Marker to always be sure what are we talking about. 2)tell me the real world value of the resistors R15 to R22 ¿Did I mention I don´t trust the schematic very much? 3)Draw the Molex connector on the schematic, number the pins (they´re usally labeled somehow) and then measure the voltage to power supply ground from every pin. I strongly suspect that your -B (-47V) is missing, making *everything else*  measure close to +47V. Other possibility is that both R20 and 22 are open. 4)Please measure some voltages for me. The red ones (V01/2/3) should be measured with the black probe on the power supply ground itself and the red probe where indicated. I suspect V03 (-B) will be missing at the board, in that case trace its path , specially on both sides (male and female) of the Molex connector. IF that is OK, measure V04 to 09, placing the black and red probes where indicated by the respective colors. Good luck.

Dear Muttomatic: build the excellent lamp limiter suggested by Teemuk, and plug your amp into it *without* hooking the speaker, no signal, all pots on "0", etc.
Measure the voltage at the "hot" speaker out, probably you will read around +B (close to +40V) as you did earlier. Then measure the voltage across the power transistors (collector to emitter) , (probably either very low *or* close to 80V)  and across base-emitter (around 500mV). Write a table such as , let´s say as an example:
"Q 4 - 2Nxxxx - VCE:80V - VBE:760mV" and so on. This particular measurement would indicate an open transistor.
Measure on the transistor pins themselves, you might have a worn or corroded socket, you might also have a cracked mica or some other unseen short.
Even better, hand draw a schematic of at least the end of the power amplifier: output transistors, driver transformer, and very specially the string of biasing resistors (it might include some thermistor ) from +B to -B. Probably most of it is in the board you posted.  Bye.

Hi Armstrom.  Please post some pictures, front panel but even better: chassis insides, as detailed as possible, showing the output and driver transistors. Also: what´s the proble m? Thanks.

1)Somewhat old design but should work reasonably well. However, no matter what the brochure says, it has *NO* short protection;so just be careful.
2) If you already have the transformer, use it. If you have to buy one, a single 30 to 36VAC ;  60VA or higher transformer, rectified with a bridge (4 diodes) will be more efficient and somewhat easier/cheaper to find.
Good luck with your project.