Another cry of help!

[Malka07]

Thanks Phillip for helping me out, i just looked through all the papers i got with the amp and found a sheet with the test voltages on it. It shows all the points to test and what they should be...so when i get a chance i will check them and post the results. When you say check for continuity do you mean to just visually check and see if everything is where it should be? or do you mean to get the multimeter out and check stuff like resistors? sorry im just a beginner and need everything spelt out for me!

btw if it is something to do with the HT supply...the only things i have changed on the psu tag board is a few wires and the five capacitors. I have never used screw terminal capacitors before...and hope that i have connected them ok. maybe this is the problem?

anyway thanks again everyone for helping i really do appreciate it and im learning a hell of a lot as i go along.

Alon

[pre65]

Originally Posted by Malka07

When you say check for continuity do you mean to just visually check and see if everything is where it should be? or do you mean to get the multimeter out and check stuff like resistors?

Alon

Both ! Using the circuit diagram use the meter to check that items supposedly connected are actually connected,and trace the circuit through.

Pay particular attention to items you have played with.

Where the circuit shows a capacitor with half black and half white symbol,the black side is negative,so double check that aspect.This applies to the power supply caps C1,C2,C3,C4 & C5.

When you have done that power it up and check those voltages.

[Malka07]

Just one quick question before i begin...

...when i check the voltages, im assuming that the valves should be plugged in, if so when i turn the amp upside down so that i can get inside, will this not put to much pressure on the valves? or is there another way?

Also does the Amp need to be connected to speakers when checking voltages?

ok i lied that was 3 questions

[JonnieBoy]

Yes the valves must be fitted.

I found somthing to support the amp by the chassis to take the weight off the valves! (toolboxes, books, bricks, whatever fits)

Yes connected to speakers (or a dummy load).

Be careful! Slow, steady, and methodical!

Good luck with your diagnosing

[Malka07]

Thanks for the help JonnieBoy, i will have a look around the house to see what i can prop the amp up with.

Right....slow and methodical.....right....here goes...

....only joking

[Malka07]

Whilst checking Resistances today, i came across two resistors in the PSU tag board that are giving 0.0 resitance on the multimeter they are r3 and r4.
i wonder if this is the problem im having. What is strange is that these resistors were not changed this time round and they were working perfectly and are pretty new, so why have they failed? as i didnt touch them this time round. They are Kiwames...maybe the fault still lies else where and it caused these resistors to go open(if that is the correct term?..lol)

Any idea's?

on a positive note everything else seems to be correct...all other resistors correct and continuity correct too.

Alon.

[Shian7]

Originally Posted by Malka07

Whilst checking Resistances today, i came across two resistors in the PSU tag board that are giving 0.0 resitance on the multimeter they are r3 and r4.

That's actually a short circuit.

It may be worth lifting one leg and re-checking, if it's still 0ohms they're knackered.

[Malka07]

ok now this is really weird!!!

I just noticed that one of the solder tags from one of the new capacitors was touching the chassis, i have just fixed that problem and remeasured the two resistors that were giving 0.0 and they are now both showing 49.5...but they are meant to be 100k?

Does this make sense to anyone?

The other two resistors (R1 and R2) in the psu are showing correct 99.8

[Cobblers]

So the resistors are now connected in parallel.

[Malka07]

Originally Posted by Cobblers

So the resistors are connected in parallel.

Yes, but on the scematics they are meant to be conected in series, the first two resistors are correct and the next two are connected exactly the same way as the first two...except that they are returning a different value?