Hi All, So I am really hoping to get some help with my Zkit1 build, I finished the board and installed it in the plinth which I laser cut at the school I teach at, I did the same plinth with my TT Lenco GL75 build, and I recently built a pair of the Madisound BK-12M folded horn kits, which sound awesome so I am super excited to get this great little amp to work, my pre-amp is a Croft Audio MKII from the U.K and is hosting twin Telefunkens and a Mullard.
So here are the problems I am having....test point A starts strong at 430 then drops to 230v and holds, test point B does the same and holds at 202v, point C starts at 11v then after 10 seconds rises to 28v and holds point D is at 1.8v and holds. If I leave the amp powered for about 60 seconds the 1K 5W resistor starts to smoke constantly and gets rapidly worse which is when I power down. Solder points all look good, the tubes are NOS Russian and were supposedly tested so are presumed good and they all light up fine; twin matched 6P15P and a 6N1P.
Any ideas?
Jinks.
I wanted to post images but this forum does not allow it yet!!!!!!!!!

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Today I purchased a Capacitance meter online so I can check the caps, I tested the Edcor and it is a solid 320V on both Red outs, I went over all the parts again and they are all correct and test okay, no dry solders, still have no idea why the test points are so out of wack and the 1K 5W starts to smoke after a minute.
Just tested again all parts out of board and then back in, still getting the same results which at least is continuity..right point A is 230v POint B is 202v Point C is 23v and D is 1.65v from pin 8 on the input tube and 1.75v from pin 3.

Still waiting for any help from anyone or thoughts on how to precede.
If this does not work soon I am going to scrap the PCB and go point to point.
Thanks for reading......

m.

Hi Steve, Thanks for your reply, it is beginning to feel like the 40 days and 40 nights of testing and re-testing! So I just now disconnected the RCA and speakers wires and volume wires and then tested the voltages again, the resistor now glows red hot and the voltages after about 30 seconds go to their resting places of 230, 202, 23 and 1.75
I feel like Dr House and it is never Lupus but suspects Thyroid but it's actually Rabies!

Update-
Today I re-soldered everything using flux to get a really good solder then cleaned the board with alcohol. Next I shortened all of the input and output transformer leads to have clean signals, This unsurprisingly did nothing to my voltage test readings...still the same. So I am thinking it is something big, like a bad cap or diode or maybe the output tubes are bad or wrong, so I ordered some new tubes, new 300v caps and diodes and we will see if that does anything! This was supposed to be an easy build!
it's on a PCB after all!!!!

Thanks Steve! I have something new to report! with the output tubes removed...the 1k 6.5w does not even get warm! and the voltages at A point are 423v at B-376v at C-0 and at D-3.3v and 3.2v
So am I right in thinking the output tubes are wrong or shot? I have ordered NOS 6P15P-EV's I have a feeling that the ones I have now are not EV just 6P15P would that make a difference?

Thanks again,

m.

Thanks Steve for your diagnostics! I received my Capacitance meter in the mail and checked all caps and they are all good, I changed the 5W resistor and diodes just to see and of course no change, the tubes are definitely to blame, I ordered a matched gold plate pair from Russia and now will just wait for them to arrive!
I will let you know....fingers crossed.

Many thanks again,

Mathew.

WOW,
Been away for awhile and just read your horror story! That must have been very frustrating. I'm very glad that you got her up and running(I'm assuming?) As for tubes, I wouldn't TOUCH a Chinese tube even if it was free. For any of my Decware amps, I would buy directly from Steve.
I have an early version of this kit back when Steve included all of the transformers and components to complete the kit. Since then I've updated to the new board with the CCE mod, and she still purrs very nicely.(using Russian tubes from Steve) I have a Mini Torii, and I use that the most now!! Just love it!! I haven't touched it as far as tube rolling, Steve voiced this amp VERY NICELY!!
Best to you,
John