Wurlitzer 206A odd static sound

[folkswaggin]

Have a Wurlitzer 206A that makes an intermittant static/hiss/whistling sound.  I'd very much appreciate any assistance in pin-pointing the cause. 

I added all the components to the amp board from Vintage Vibe's 206 vibrato & line out conversion kit:
https://www.vintagevibe.com/collections/wurlitzer-kits/products/wurlitzer-206a-vibrato-aux-output-kit

Also replaced outout transistors (TR11 TR13) and other transistors from BustedGear:http://www.bustedgear.com/part_transistor.html
(TR1, TR2, TR3, TR4, TR7, TR8, TR9, TR10, TR12, TR14, TR15, TR16)

And installed switch with dummy load to turn internal speakers on/off

The instrument makes sound, vibrato and 1/4" aux output work but there is a static, frying eggs and high frequency whistling sound sometimes.  On occasion the instrument sounds just fine with a low noise floor and then sometimes the noise comes in.

Listen to sound:  https://crickers.rocks/wurlitzer206a-amp-noise/

Thanks,
David McCracken

[melveyr]

I've had similar sounds before. There is likely some small piece of debris stuck on the pick ups, probably so small that you can't even see it. I would thoroughly vacuum the instrument, especially around the pick ups. Also to help pinpoint where the sound is coming from you can blow some air (Even just thru a straw) at different parts of the pick ups, and you might even be able to just dislodge it that way.