Marshall AVT150HX Schematic

[fabb2004]

Anyone know where I can get a schematic for a Marshall AVT150HX?

Thanks

Kirk

kirk.fabbri@gmail.com

[vintagekiki]

May be help Marshall AVT150 Schematic

[fabb2004]

Marshall Schematic

Thanks!!! Do you know if this is the whole thing? I didn't look real close but I didn't see anything referencing the actual power amps? Any idea? Thanks though this should def help!

Kirk

[Enzo]

The X has a different power amp from the plain.

Send me an email asking for the AVT150X

[fabb2004]

Yes the schematic I need is for the AVT150HX. Do you have a complete set for that amp? Let me know, thanks again!

Kirk

[Enzo]

Send me an email asking for the AVT150X

I could have sworn...

[fabb2004]

Marshall AVT150HX

Can you send me a complete set of schematics for a Marshall AVT150HX? Thank you.

[Enzo]

Ahem...

Send me an email

[trizton]

avt150hx

What is your e-mail enzo? i have a avt150hx blowing fuses immediatly..there are no IC's as described for the avt150h..and any info on what could cause this..the valves?

[Enzo]

I quit displaying my email, too many emails.

This should be what you want, the rest of the amp should be the same as the 150.

[fabb2004]

Problems with the AVT150hx

Yes it could be the valves. Try pulling them all out and see if it still blows the fuse. If it doesn't then something is wrong with either the tube(s) or biasing circuitry, both, or even something else related. When you put them back in, do it one at a time to see if you can narrow down the problem to one tube or stage.

I was in Guitar Center (GR, MI) and they had one of these amps that they were selling cheap because it wouldn't power up. I heard mention that it was the main power transformer. Due to the cost of the part and what they wanted for it; it was just as expensive to buy one new or off ebay in working condition so I never messed with it.

Good luck!

[trizton]

Thank you Enzo

Just wanted to say thank you ill take another look at it after wrk tonight.

[trizton]

avt150hx blowing fuses

Ok here is where im @ i went thru several fuses backtraking the wrong way..ends up if i unplug the primary leads to x-former no fuse blows..im reading 1.7 ohms on primary..till i fix that it doesnt matter what downstream is..any ideas? i dont have a megger..Im sad i got myself into this situation..this is for an older guy in maintenance dept..his sons have a band and he thinks i can fix anything..yes i have a diploma in electronic's/computers but that was my core for associates in robotic's / automation..the 1.7 ohms doesnt suprise me as a primary ohmage but i may be wrong..and the only fuses i could find close at work happened to be 3.5 amp@125 volt..but with secondary unplugged..it shoulda been fine..im thinking primary is faulty..doesnt seem right though..doeasnt show open or anything to ground..not even in the meg's. HELP please

[Enzo]

The power transformer? If the secondary is not shorted to the primary, and neither is shorted to the frame, that is about it for your meter. Two turns could be shorted together and your meter couldn;t tell the difference.

RG has a nifty simple transformer tester on his Geofex web site.

But really, disconnect ALL the secondary wires - 2 secondaries, 6 wires. Now does it pop fuses? Disconnecting the primary leads will almost always stop an amp from blowing fuses, after all that disconnects the ENTIRE circuit.

Look up "light bulb limiter" make one and use it. Or use a variac and ammeter.

Are the secondary wires on the right posts? If it blows fuses with NO secondary wire connected, then yes, I suspect the transformer. But it really is the lowest thing on the list.

When an amp blows fuses, the list starts about like this:
shorted output devices
shorted main rectifiers
shorted low voltage rectifiers.
main power rail shorted to ground
shorted filter cap
mis-wiring

[trizton]

just got home from wrk

Yes all secondary wires disconnected and it blows fuse..I dont know why i didnt ohm the secondary's out last night..I think thats the problem..they are both reading dead short to .1 ohm..they are not reading to each other but both the 18 and 32v secondaries show no resistance to there assigned common. I blame the BEER =p.