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577/Repairs: Difference between revisions
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→Symptom: Unit shows signs of power but no CRT Activity. Yellow Collector caution light comes on, indicating power.
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99% sure this was my problem. | 99% sure this was my problem. | ||
Replaced all three caps with new versions, same specs. | Replaced all three caps (as a precaution) with new versions, same specs. | ||
Replaced R786 and R766 (3.9 Ω 1/4 W 5% Carbon Comp.) 786 was open 766 had drifted to 5.16 Ω. I used metal film 1/2 W 1% as replacements, this was what I had on hand. | Replaced R786 and R766 (3.9 Ω 1/4 W 5% Carbon Comp.) 786 was open 766 had drifted to 5.16 Ω. I used metal film 1/2 W 1% as replacements, this was what I had on hand. | ||
Powered up and | Powered up and found that all rails now function with the +30V rail well above factory specification. | ||
Simple fix: Someone had been "adjusting" the +/-30V Trimmers to try to "fix" the +30V Power supply rail (this did not work). | |||
Adjusted +/-30V Rails to specification and reassembled PS to Chassis. | Adjusted +/-30V Rails to specification and reassembled PS to Chassis. | ||