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Old 17th Mar 2018, 3:06 pm   #53
OldTechFan96
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Join Date: Jul 2017
Location: Newcastle Upon Tyne, Tyne & Wear, UK.
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Default Re: Bush VHF 81 Restoration

This morning I checked the HT voltage using the same setup as last night. Now the HT is 295V! Nothing has changed since last night so we might have an intermittent fault on our hands. I'll try and source a replacement rectifier.

The resistance between the chassis and the disconnected HT wire is 29M ohms on all wavebands.

When HT is connected the audio O/P valve does get very hot. How warm should these valves be? I don't think C49 is leaking as only a tiny (18-25mV) DC voltage is measured by my DMM on the grid of V6.

Quote:
Originally Posted by Station X View Post
It's difficult to say what's been pulling the HT down. I would suggest disconnecting C49 manufacturer's sheet (that capacitor) before reconnecting the HT to the set. Monitor the HT voltage continuously and switch off if it takes a dive.
This will be the next thing that I'll check.
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