I'm looking at a T4XC for a friend. It needed new output tubes when he got it, they showed overheating marks on the plates and the cathode resistors were burnt out. With replacements fitted and the neutralising adjusted it seemed to work fine.
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A few weeks on he's reported a problem; transmitting on SSB ok, but on releasing the PTT it sometimes stayed in tx and the only thing he could do was turn the power off. I asked if he had the VOX on, he said thought not, and operated the switch to check. It went straight onto tx and now goes to tx the moment power is turned on, regardless of the VOX switch or mic gain settings.
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Has anyone seen this problem before? Any suggestions on possible culprit circuits?
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Thanks and 73,
Steve G8GSQ
