I have a Kris Mach 3 that I bought non working I replaced capacitors, diodes and put good tubes in it and it is working now but not like it should. After turning on amp and giving it some warm up it dead keys about 40w and swings to70-85w but the longer you key down the amp the more the watts will go up. If I key up and hold deadkey a couple of minutes watts will go up to 70w deadkey and amp will swing to 175w but unkey wait 2-3 minutes and and amp will be back to 40w swinging 85w its almost like resistors are draining or bleeding power in standby mode. It is a good amp for long term talking because you can keep watts up but it needs help Any help or comments are welcomed. Thanks Jimbo165
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Kris Mach 3 low watts
- Thread starter Jimbo165
- Start date
Are you using an external pwr meter to measure the output?
Amps that have been thrashed sometimes display this slow increase. What does the specs say about the input power and output power. Have you checked your radio on its own to see if the output is stable ? A USER MANUAL & CIRCUIT DIAGRAM are you best friends as they will tell you what the various components are and most times what voltage are at various points. The tube specs will also tell you what voltages are required in the various pins. !
I would then check for burned components or discolored components, dry soldering joints etc. Then check the various voltages in the power supply.
Warning : there are voltages inside the amp that can kill you DEAD. If you dont know what you are doing then DONT!
Amps that have been thrashed sometimes display this slow increase. What does the specs say about the input power and output power. Have you checked your radio on its own to see if the output is stable ? A USER MANUAL & CIRCUIT DIAGRAM are you best friends as they will tell you what the various components are and most times what voltage are at various points. The tube specs will also tell you what voltages are required in the various pins. !
I would then check for burned components or discolored components, dry soldering joints etc. Then check the various voltages in the power supply.
Warning : there are voltages inside the amp that can kill you DEAD. If you dont know what you are doing then DONT!
Amp is 1 driving 2 tubes should be in 175 to 200 range have looked for any burned or componets not looking normal but all looks good. Amp will put out correct wattage when deadkeyed for two to three minutes before talking but let amp set on then keyup watts will be in 75 up to a 100w for normal conversation and if you keep using amp as in long term talking wattage will creep up. I have already replaced capacitors , diode were checked and I put good tubes in. Good little amp even now but should produce more. Just wondering if bleed down resistors could cause this? Thanks for comments
old resistors do change their values over time. If you disconnect ( unsolder ) one leg of each resistor then measure across it to get its value. If its far off, then replace it with a suitable value/wattage one. You could even look at the wiring connections. The power supply could also be dropping under load.
So, uh... Where did you look?
Try here. https://www.tubesandmore.com/products/capacitor-jj-electronics-500v-axial-lead-electrolytic
73
Try here. https://www.tubesandmore.com/products/capacitor-jj-electronics-500v-axial-lead-electrolytic
73
Closest thing I found online is the Mach 3B. Yours lacks the suffix letter after the 3.
It's here: http://www.cbtricks.com/Amp/kris/mach-3b/index.htm
With any luck it's close to the same thing.
73
It's here: http://www.cbtricks.com/Amp/kris/mach-3b/index.htm
With any luck it's close to the same thing.
73