Marshall Valvestate 2000 avt150 fuse help plus.

[Br_ad]

So for resistance I shouldn't be reading ohms? because yes, 3-4 ohms is what I meant. What do you mean by "low resistance reading"?
By the way I appreciate all of your guys help.

[Jazz P Bass]

So for resistance I shouldn't be reading ohms? because yes, 3-4 ohms is what I meant. What do you mean by "low resistance reading"?
By the way I appreciate all of your guys help.

Pretty bizarre statements.
A "low resistance reading" IN OHMS is something like 3-4 ohms.
I made the statement about the fact that you are "reading across the output devices terminals: as a hint as to what you should be reading.
Think about how a transistor works.
It is an adjustable switch.
Off/ On.
So, if in a static no power state, the transistor has a low resistance, it obviously is shorted, as in not "OFF".

[Br_ad]

Sorry If I'm getting on nerves, If I had a reading of 0 ohms would this be no resistance? whereas like you said 3-4 ohms is low resistance. or Do I have that backwards. And Don't I want to have 0 ohms for resistance when the power is not on. Again sorry if I'm a bit slow on all of this I'll get there in the end.

[Enzo]

The chip should not have zero ohms or 3-4 ohm either one.

The ONLY difference between the V and H chips is the shape of the legs. And no one stocks the H version anymore anyway.

If one module is burnt up, replace both. Even if the other one seems OK. It will have been stressed by the bad one.

The little boards are easy to unplug and remove from th heatsink. You'll get some grease on you, that's life. You can replace the IC on them on your bench.

CLipping the 15 legs off and trying to solder to them is silly. Cut the IC off, then heat the solder on each remaining leg and pull it out with pliers. Now with all the legs removed, clean the solder from the holes, and solder a new IC right into the holes.

[Jazz P Bass]

Between pin 13 & Pin #14 should read a high resistance.
I would consider anything from 1 thousand to 1 million ohms high resistance.
The same for pin# 15 to #14.
Zero ohms is low.
Lower than 3-4 for sure.
In fact it is a dead short.
In that condition you do not have a good transistor, you have a piece of wire.
Both parts are bad.

[Jazz P Bass]

Alright. I pulled a brand new TDA7293 out of my spares cabinet.
Measuring resistance yields a 2 million ohm resistance between output pin #14 & either B+ or B- rails. (Pin 15 & 13)
On diode check:
Pin 14 Black lead of meter/ pin 15/ Red lead reads: .584
Reverse the leads & reading is open circuit.
Pin 14 Red lead of meter/ pin 13 Black lead reads: .584
Reversing the leads reads open circuit.
That is how it should read from the factory.
The .584 readings on diode check is the forward voltage drop of the collector /emitter junctions. Which is good.

[Br_ad]

Ok, I've had the boards off the whole time I might be wrong but the chips I found on the previouse website seemed like H's. I could be wrong, but will I be able to attach the board in the same way if I use the Vs

[Fragger]

If you go to ebay and search for "5x20 4 amp slow" you can find 10 for ~$9 including shipping from Florida.
If your patient, you can order 50 for ~$8 from Hong Kong. ;^)

[Jazz P Bass]

Ok, I've had the boards off the whole time I might be wrong but the chips I found on the previouse website seemed like H's. I could be wrong, but will I be able to attach the board in the same way if I use the Vs

You want the "V".

[Enzo]

And Mouser has 20mm 4A slow fuses in stock for 66 cents in unit lot. Bussman brand, not Wang Chung