My first HF rig: a Kenwood TS-530S which came to me through a club connection. This is a 160M-10M HF Transceiver of hybrid design – that is, mostly transistor circuits but also with a few tubes, namely one 12BY7 driver stage tube and two 6146B beam power tubes for the final RF amplification stage.
While testing this with some club veterans we got signal reports of scratchy, buzzy audio. The usual cause for this type of audio noise is bad filter caps Since this rig is of older vintage, my Elmers recommended replacing the final stage electrolytic filter capacitors anyway – good advice for any old rig!
This is a look at what was involved. Actually, just little bit of soldering after I removed the caps from the holder clamps on the other (top) side of the main chassis. The new caps were the same diameter but half the height, reflecting the advances made in components in the past 20-30 years.
I got a replacement kit on eBay from VE3PVS http://www.ve3pvs.ca, Peter Rogers. He was great to deal with and has complete recap kits for various Kenwood models, which come with complete instructions and include new replacement bleed resistors and disk caps to replace the ones shown in the photo above.
You can also get a filter recap kit from Ken, K4EAA. He has a large supply of hard to find Kenwood hybrid parts. Visit his excellent Kenwood site which features a comprehensive FAQ at http://www.k4eaa.com/faq.htm.
I’m getting excellent signal reports now and will complete recapping with the rest of the boards, one at a time as Peter suggests.