Hi Fellas,, Just wondering if a TDA 2030a can be powered up with no Speaker load to it?,, Will that destroy the Chip,, ? Thank you..

Thanks g1,, I will keep that in mind for sure... I'll install the Higher current transistors and let it run for the day to see what happens.... Thank you for your help..

Thanks guys,, It turned out to be a Dual Diode,,, I think it was still good but I replaced it with 2 diodes in series.. Yes Baxandall is a tone circuit but is also a Baxandall compensation system in SS amps,, I don't know much about it at this point but hopefully will be able to find more information on it.
That thing looks just like a Tantalum Cap for sure LOL,,, The first time I tested it I did a diode test and got over 1.1 volts.. I thought,, that's strange then I did do a cap test on it and got 60 some odd pf's,, really threw me for sure.

Hi Enzo, g1. Thank you for replying,,

The Voltage imbalance seemed to have been cause buy a cracked pcb trace.. I've repaired that and the voltage is now spot on.

The temperature difference is still there with a slight change. Got to tell you that High temp resistor reading really had me freaked but what I did was turned the amp on and left it on all day... The resuslts where..

All voltages DC and AC are completely stable.. there was still a temp difference in the Zenor regulator resistors, But I think the amp can live with that..

My initial concern and lack of understanding was the Burn marks under the original 1.2 watt 330 ohm resistors and how hot the original bridge rectifier was getting,, Those have been replaced with Higher wattage devices.. 2 watt resistors and a Higher Amperage rating Bridge rectifier..

The resistors still get hot.. I've calculated the Power consumption of bother resistors and it's just under 1/2 watt. The good thing is the even though the resistors are running hot the Bridge rectifier is no longer heating up, and compared to the pos rail resistor it's room temp,,,

I thought that I'd blown up one of the new output transistors which were fairly expensive as they had to be ordered from the UK.. But I took it out and rechecked it and it's perfectly ok...

I'm not sure if someone had been in this thing before to try and repair it but there was quit a bit of trace damage around both output transistors which i will attempt to repair this afternoon,,,,

Thank you to you guys big time for your patience and all the help,,, My understanding of SS discrete Guitar amplifiers like this TBM 25 has increased ten fold.. 

Hi g1,, Thank you for your reply and input,, To answer your questions,, The voltage drop across the 330 ohm resistor is 12. 4 volts.. So the power the resistor is dissipating is .466 Watts,, Hmm very interesting again for sure.. Not sure about the negative rail,, Just checked and getting strange voltage readings from that side now.. Transformers still getting around 21 volts A/c..

Really not sure what's going on,,, voltage drop accross the Negative side 330 ohm resistor is 20 volts.. voltage at the rectifier side of that resistor is 29 volts,,, somethings very wrong here for sure.. I'll keep looking,,

Hi, Just wanted to post the progress so far and note the findings.. I still have not found what is causing the RS Resistor for the Positive zenor regulator side to over heat,,, But I have found where the problem is..

After cutting pretty much every supply trace on the board including Positive and Negative supply rails as well as the Ground rail all in Multiple places I've worked my way back right to the zenor regulator...

With absolutely no load the Pos rail resistor still over heats.. Very interesting for sure.. I have checked for shorts and there are none,, The voltage is not being loaded down and remains constant at 7.5 volts @ around 65 Ma..

I'm thinking at this point is has to be either a Miscalculated zenor resistor problem or the power transformer is bad? I've checked the AC voltage from the power transformer at the Rectifier input(which I have replaced as well) and the voltage is spot on,,

I'm wondering if there are any other possibilities that I have missed.. There is definitively a problem from the RS resistor, to the Zenor, to ground. I just don't know at this point what it could be,, The Zenors have both been replace along with the 330 ohm resistors,, I'm wondering if the 330 ohm resistor is the wrong value but the positive rail is the only one that heats up , the negative rail is perfect.. This amp must have worked at one point,, This is getting really good. LOL,,, I think the Schematic is attached,,,

Hi Tony,, I'm really not sure what the heck it is,,, I thought it was a diode do to the placement,, I thought It might have been a zenor diode.. It's part of the Bax compensator,, so I'm thinking it's a Diode of some type,,, really strange looking for sure..

Hi guys,, just wondering if anyone can help me Identify the Diode in the picture.. It's from my BassMate 25 repair.. It turns out to be blown and is part of the Baxendal compensation system. I've tried replacing the Diode with a standard low power diode and That dropped my overheating problem to almost half the temp it was but now I'm getting crossover distortion.. Going to try different diodes In34 Germanium and a 914 just to see,, but would be nice to try and replace the original Diode,, Thank you.

Hi Enzo,, Yes I'm in the process of reading Teemu's great book,,, As you suspected and I guessed but had to try anyway,, Installing a new Bridge rectifier did not resolve the over heating problem,, So,, out comes the O-Scope... I've checked for signals at key points on the board and with the exception of a couple of locations that have no signal, what is going in at the input is coming out only larger at the output..So the amplifier is working.

I'm using a square wave generator at this point but I'm going to switch to a sine wave gen and take another look at the signal coming into the two output transistors. I will take DC voltage readings as well.

I can only keep the amp on for short periods of time so it's getting tricky to take readings. Resistors and the positive output at the Bridge rectifier are getting red hot still,, I'm not sure what took out the output transistors at this point and not at all sure if it was the over heating problem that was the original culprit.. but will keep on looking.

I did look at what you pointed out on the Schematic with regard to the drawing being incorrect and sure enough you were right,, the base and emitter of both output transistor were reversed on the drawings for some strange reason. Thank you I wouldn't have caught that for sure...

In an effort to try and prevent damage to the new parts I've installed I'm going to try and Isolate sections of the power transformer and see If I can't get closer to what's causing the problem. Will keep you posted. Thank you again for your help and suggestions.

Hi J.P. thanks for the Schematic post again,,, Hi Enzo I've replaced the zenors and the 2200uf caps as well as installed 2 330 ohm 2 watt flame proof resistors.. Yes the 7.5 volts both pos and neg are correct,, What I didn't replace was the rectifier,,, I will do that tomorrow and then put it on the scope,, I didn't want to scope it if I couldn't get the heat down some how... I'll post the results tomorrow or the next day for you,, thank you again for your help.... Yes this amp is super minimal,, but does it ever sound amazing,, I only wish I could figure out the power amp topology Traynor used.. It looks like a watered down giant 741 op amp,, LOL,,

Hi,, I am in the last stages of repairing my Bass Mate 25 SS amplifier,, I've replaced the output transistors/drivers etc.. and It works and sounds great,, slight buzz,, and 10 mV DC on the output.. so not too bad I hope,,

The problem is the 330 ohm resistor for the positive side of the power supply, the 2200uf cap and the 7.5 volt zenor are getting RED HOT...When I first started the repair I noticed burn mark just under the resistors and noticed they had used 1/2 watt resistors instead of the 2 watt resistors recommended,, I put in 330 oh 2 watt resistors and the one on the positive side is really getting hot.. I checked it with my laser and It's starting to go up into the 200 degree F area and If i left the amplifier on I'm sure the temperature would keep increasing until the resistor started on fire.. I've checked everything and replaced everything in the power supply with the exception of the Rectifier,,

I thought it may have been the shored output transistors that caused the over heating problem but those are new. I'm stumped,, Any help would certainly be appreciated...

Further update for my Bass Mate 25 repair,, I've rebuilt the power supply and everything there is great,, When I fired the amp back up,, and checked for DC on the speaker out put there was zero DC. But,,
The amp still buzzed and the transformer started to overheat.. Between turning the amp off and on for short periods of time I checked voltages at various points.. There seemed to be some type of voltage imbalance from the NPN side to the PNP side of components..
I thought I'd better start checking transistors,, I started with the output transistors first,, I checked the 1st c2233 NPN,, and it was Knackered,, I checked the second C2233 And it was hard to tell,, All the other transistors where ok.. So If I can find them I'll replace both 2SC2233 npn's and maybe even the drive transistors as well,,,

HI g1,, I switched the amp off the second I heard the Hum. Thinking hearing that is never a good thing, I'm in the process of replacing the 2200uF caps,, 330 ohm resistors(replacing them with the proper wattage values),,and the 7.5 volt 1 watt zenors( increasing that to 5 watts) that were knackered. Not sure if i have to replace the rectifier yet but I'll build a discrete device if I have to,,Those rectifiers seem to be hard to find... I'll also check the speaker for a burnt and warped coil former as well,,, Thank for the suggestion...I have a sneaking suspicion that all this damage was caused by minimal parts values,, stemming from using 1/2 watt resistors instead of 2 watt resistors and using the old Trick from TV guys.. Mount the parts that will get hot off/away from the board surface... 

I have a silly question,, Why are the power supply caps such a high value 2200uf..? Thank you.

I've rebuilt the Transfomer and installed it.. hooked everything back up and fired the amp up,,, So,, The fuse didn't blow..Good..It amplifies an input signal,,good,, but.. There is a wicked Hum coming out of the speaker.. Hmm,, The game is a foot.. If this was a tube amp I'd have a good idea,, but this being a Solid state amp mostly discrete, my first and only thought at this point is to check the 2 2200 35 volt power supply caps,,,,,

Thank you for the Datasheet J.P. I'm Found at least one problem so far with this amplifier. well actually 2.. Who ever worked on it before,, ripped the wires out of the signal input header so I'll have to straighten that out. I usually check for power at the chips so I noticed that the power light did not come on when the on/off switch was activated.. I checked the Secondary windings and they were good,, but.. there was no continuity in the Primary winding so,, OUT came transformer and the tare down begain... I figured it had to be a burnt winding at first but noticed absolutely no smell or dis color .. After the plates were removed I separated the primary from the secondary(which was done quite easily because of the thought put into building this transformer(Thank you China)). Unwinding the Kaptan tape still no burnt wires,, I'm thinking cold solder joint,, then there it was!!!! Dun,,,dun duuuuuuun,,, The culprit.. A Chinese made wafer Fuse... Never ever seen one before.. Buuuuuuuuuuugger... so out it will come and I'll solder the wires together and install a fuse outside the transformer.. after I get it put back together,, Will be interesting to see what blew that fuse.. if anything,,,, Here's a picture. for the curious.