Help! KAT 6550 schematics and instructions needed

[LSfarzo]

Hi guys.

I'm very sad since I've lost my KAT 6550 schematics and instructions

The worst thing is that my great KAT has gone out of order... and only then I found no schematics around!

The problem is that one of the two rectifier heats really a lot and the choke begin to buzz very loud ...
I need to double check all the voltage checkpoint and see what has gone wrong.

Please could you be so kind to send me a copy of the complete instruction manual if you have them?

Thank you
Luca Sfarzo
Italy

[colin.hepburn]

Hi Luca
You Have PM
I have KAT 6550 schematics and instructions
in Part

[bob orbell]

Hi Luca, I have had just that problem with a members 6550, the balancing resistors that someone had fitted to the AC side of the 5U4 valves had gone OC on one valve, so the high voltage DC was half wave, do you have these resistors on yours?, they were a mod. to stop rectifier flash over. BOB in cold wet England,

[colin.hepburn]

Email sent Luca

[LSfarzo]

Hi Bob,

thank you for your hint.

As far as I have understood from your reply, those resistors are a mod. I remember that my only design mods were the zener diode bridge and some other minors. I do not not remember I modded the AC side of the rectifier valves.
All my other mods were about swapping caps/resistors/cables with better versions (AudioNote, carbon and so on).

Colin has been very kind to me, too, but, unluckily, he has only a part of the KIT instructions.

So I'm still looking for someone who can kindly post me such document (a scan version fits the same !).

Please, If you have additional ideas on what may happened, and what I could check, let me know!

Best regards,
Luca

[colin.hepburn]

Originally Posted by LSfarzo

Hi Bob,


Colin has been very kind to me, too, but, unluckily, he has only a part of the KIT instructions.

So I'm still looking for someone who can kindly post me such document (a scan version fits the same !).

Please, If you have additional ideas on what may happened, and what I could check, let me know!

Best regards,
Luca

Yep sorry I sent the wrong one I have resent the KAT 6550 but only in part if anyone can help with the full manual for luca pleas pm him

[bob orbell]

Luca, I have full instructions for 6550, can you PM me with your email address and I will send it to you by meams of my Janet, from her place of work (weetabix), can't do it from home. Do hope this will help you, prago.

[bob orbell]

Luca, looking at the power supply cuircuit diagram, you can cheak with your DMM clip one lead to the earth post, remove both 5U4 valves and switch on, other lead to pin 4 then 6 should read min of 420 volts AC at both valve sockets, you can do this without moving the amp, don't forget looking from the top, the pin no's are read anticlockwise. If you do have the correct voltage, you may have a dead valve . BOB

[Greg.]

Hi Luca,

Here is the mod referred to regarding balancing resistors for the 5U4's.

http://www.world-designs.co.uk/forum...ead.php?t=3859

I have the complete instructions and diagrams in PDF format for KiT6550 which can be sent to you immediately. Send me your email address by PM and I send onto you.

Greg

[bob orbell]

Greg, that's good of you, it will save my better half doing it, also, member Shane has asked me by PM if I could send him same, I have his email address, if you could do same for him that will be good, if you will please PM me for the email. BOB