Marshall Valvestste VS100H amp

[e_c_mccollum]

I need the output transistor numbers for :

T9, T10, T11, T12

It currently has four differnet power transistors in it. Heatsink grease is everywhere indicating inexperience.

I am looking for a schematic if possible.

[Twist]

The VS100 uses BDV65 for T9 & T10 and BDV64 for T11 & T12. I have the schematic for this model (VS100).

[Enzo]

Don't bother looking for the BDV types, use TIP142 (NPN) and TIP147 (PNP) in their place. Yes, it is a good sub, even Marshall used them after a while.

I have found in my over 50 years of soldering experience that I cannot keep silicone heat grease contained. It will go where it wants and I am powerless to stop it. I will admit to leaving globs of it behind in these amps.

I too have the drawings scanned. Take Twist up on his offer, or email me at:
tmenzo at msn dot com

[Amp Kat]

Watch out for the tube retainer also. It will dig into the pcb creating a short from ground to the trace it's digging in and cause the rails to short and the 15 volt regulators to fry. Make sure all your rail voltages are present before replacing those transistors then bring it up slow and make sure they are all coming up nicely and not staying at zero vdc. Very easy to fry components a second time if the rails aren't right.

[e_c_mccollum]

Schematic

Twist, email me VS100H schematic (pdf format) at

e_c_mccollum@hotmail.com

[Twist]

Did you get the schematics? Let me know if they're the right ones?

[e_c_mccollum]

I love schematics

I recieved them and they are the correct ones.

Marshall won't send me them because I am "not an authorized service center". The only authorized service center in my area does a "half job".

I believe piss poor resoldering started this mess.

[e_c_mccollum]

I am having alot of trouble finding the mjf122 driver. Any sugesstions?

[Enzo]

Mouser - MJF122 $0.86 Currently out of stock but on order, estimate 1/28/8
Allied - no
Digikey - non stock item, but if you want 800 of them...

They are electrically similar to the TIP122 (ON Semi says so) so:
Mouser - TIP122 $0.35-0.46 in stock
Allied - TIP122 $0.35-0.46 in stock
Digikey - TIP122 $.50 many in stock, listed as obsolete types.

Difference between MJF122 and TIP 122 is that the older TIP122 has the metal tab -the collector - while the MJF122 is the all plastic isolated package. So if it is mounted to the heat sink, you would have to ensure it was insulated from it. I have done that many times.

[e_c_mccollum]

Good advice. The Tip122 has to be insulated. The other side of the heatsink has a tip147 output with a metal tab. Thanks.........

[e_c_mccollum]

What can I replace 2SA872 transistor and bzy88c zener diode with?

I have a project saved with Mouser electronics. I hope they have the subs, if any?

[Twist]

If your talking about D8 on this amp it's a 6.8 volt zener. You could use a 2N5400 for the 2SA872 or dare I say NTE 288 (for fear of being attacked).
The 2n5400 is a PNP and has the same pin out.

[e_c_mccollum]

But according to the website,

http://www.ortodoxism.ro/datasheets/...or/mXwvstt.pdf

the pinout does'nt match the fairchild 2n5400. Does'nt matter, as long as it will work, I will switch the leads of the 2n5400. Also, the gain is less than the 2sa872.

[Twist]

Your right, sorry bout that. It was late last night and I just recalled using that substitution a few times.

[e_c_mccollum]

Maybe Enzo has an idea for a sub for 2sa872?

Marshall gave me a part number but not a sub. It takes too long to order parts thur a dealer.