need schematics for Crate CR-1

[Enzo]

There is nothing a circuit can do to make a shorted part look not shorted. SO measure them in circuit. If they seem shorted, THEN remove them and retest out of circuit. But if they show not shorted while in circuit, then they are not shorted.

[Jazz P Bass]

Looking at the schematic, there is a 100 & a 0.33 ohm resistor from the Base to the Emitter (Q9 & Q10).
So any reading of Less than that would indicate a shorted transistor (Base to Emitter).

A more common short is across the Collector/ Emitter junction.
That would apply a dc voltage to the output jack. (check for that)

If the drivers are shorted C to E, that will confuse the reading of the C to E reading of Q9 & Q10.

[Hanger-18]

Looking at the schematic, there is a 100 & a 0.33 ohm resistor from the Base to the Emitter (Q9 & Q10).
So any reading of Less than that would indicate a shorted transistor (Base to Emitter).

A more common short is across the Collector/ Emitter junction.
That would apply a dc voltage to the output jack. (check for that)

If the drivers are shorted C to E, that will confuse the reading of the C to E reading of Q9 & Q10.

I plugged it in with a 3 A fuse because I didn't have 1 amp. Shut down immediately after seeing smoke. When I got the chassis out only hot part by that time was ONE of the .33 power resistors.

[Jazz P Bass]

Not a good idea there with the higher rated fuse.

First off:
Do Not Connect A Load To The Output.
Not until the output section is stable.

Second: Remove the output transistors & check them.
Once they are out, the drivers can be checked in circuit.

Third: Build a Lamp Limiter.
It will limit the current that the failed amp is trying to draw, thus giving you a chance to find a voltage that is way off, which may lead to the failed component(s).

Fourth:
With no load, measure the volts dc on the output jack.
Take note of the polarity as this may be a hint to which half is bad.

When repairing solid state amps, they require attention to detail.
They are a balancing act between the + & - power rails.
So take your time, study the schematic & find what is obviously a failed component(s).

[Hanger-18]

Not a good idea there with the higher rated fuse.

First off:
Do Not Connect A Load To The Output.
Not until the output section is stable.

Second: Remove the output transistors & check them.
Once they are out, the drivers can be checked in circuit.

Third: Build a Lamp Limiter.
It will limit the current that the failed amp is trying to draw, thus giving you a chance to find a voltage that is way off, which may lead to the failed component(s).

Fourth:
With no load, measure the volts dc on the output jack.
Take note of the polarity as this may be a hint to which half is bad.

When repairing solid state amps, they require attention to detail.
They are a balancing act between the + & - power rails.
So take your time, study the schematic & find what is obviously a failed component(s).

Thanks. I had just picked it up from the flea market DOA and had about 30 minutes before taking the wife to the store. I have a light bulb limiter variac, etc. I have a Good working CR1 and paid $20 bucks so this would be parts if it was unfixable. I saw it had a burnt fuse and plugged it into a power strip and knowingly used the lowest one I had. I realize it wasn't smart. I am going to re approach the situation properly now. I also have #2. CR45's one bad reverb the other output amp is Dead. I am going to check the output transistors and the rectifier diodes. I'm not giving up on these as I think these wood crate amps are just too cool!

[Enzo]

We'll try to help with whatever you have, but please only one amp per thread, start new threads for other amps.

[Hanger-18]

We'll try to help with whatever you have, but please only one amp per thread, start new threads for other amps.

I will. I only posted about the CR1 here because I found the schematics here. I am focusing on this amp. I have many other projects and will post separately. Enzo I have used your advice many times just by reading replies on other threads. Can't wait to finish this one...