Quote:
Originally Posted by Electronic M
The 2 cobramatic changers I've owned both worked fine after a recap and getting the mech working...If you haven't recapped it yet that would be my first move. If it has fresh caps check tubes and resistors. If it still sounds bad try injecting audio and seeing if it still sounds bad. If it sounds bad with injected audio the problem is likely in the speaker or output transformer, but if injected audio is good then either the cart or the osc circuit that converts it's output to audio is bad.
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it has brand new capacitors in the amplifier, the only capacitors that havent been changed were the power supply filter caps which are still working. The thing I have noticed on it is that it seems that it has a grounding issue betweem the cartridge and the amp because it has a hum to it that goes up and down with the volume control and isn't the same hum as the hum you get with bad filter caps.
Also this Cobra-matic changer uses an Astatic model 99 Powerpoint "cartridge" (which is basically a needle and cartridge in one unit that plugs into the tonearm) so the only thing that could be bad would be the needle/cartridge assembly itself which could always be possible seeing as it was a NOS Needle/Cartridge assembly I had bought for this unit.
I've changed out the tubes several times with other known good 50C5 and 12AU6 and 12BA6 tubes and it doesn't sound any better, and the speaker is still good it doesn't have any damage that I can see of.
I do have a Sonotone 2T Cartridge and needle assembly that I could try and install in this record player in place of the original Powerpoint cartridge assembly but unfortunately the tracking weight would be different as the Sonotone cartridge tracks lighter than the original cartridge does by a couple of grams and I don't know how to adjust the tracking weight on these old cobra tone arms.