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[N0XWR]

Lou,  I always enjoy and appreciate your knowledge of amps. Agreed on all your comments about the 2500.  An access panel on the bottom sure would have been nice.  Mine was gifted to me and is now working FB.  It is of later production, built in March 2007.  Original tubes and full output. For anyone interested, the blower in mine was a Dayton 4C761.  The motor had sleeve bearings and was getting noisy.   I found the exact replacement which is a Dayton 1TDN4.  The motor has ball bearings and runs quieter.   I purchased it from Grainger for about $80 including shipping.   73 Jerry N0XWR

[KM4AH]

W4EMF has put an access panel in at least one HF-2500.  And, he is one of those guys that can do it like a manufacturer or better.   Right machine for the job sort of thing, and some talent .

[VE7RF]

Lou,  I always enjoy and appreciate your knowledge of amps. Agreed on all your comments about the 2500.  An access panel on the bottom sure would have been nice.  Mine was gifted to me and is now working FB.  It is of later production, built in March 2007.  Original tubes and full output. For anyone interested, the blower in mine was a Dayton 4C761.  The motor had sleeve bearings and was getting noisy.   I found the exact replacement which is a Dayton 1TDN4.  The motor has ball bearings and runs quieter.   I purchased it from Grainger for about $80 including shipping.   73 Jerry N0XWR

Dayton revamped it's entire blower lineup years ago. The new 1TD series is superbly made.  Aside from now using ball bearings, the motor's also run cooler, quieter, and draw a lot less current..and price is cheap.  Kooltronics and EBM-Papst  are priced into the stratosphere, beyond absurd.   

[WX2S]

Coda: The amp runs fine. The low plate voltage reading was spurious, probably caused by deteriorated carbon-composition resistors in the metering circuit. Measured plate voltage was 2600, right where it should be.

The failure to put out power was likely caused by operator error on my part. Our best guess is that I'd reversed the RF IN and RF OUT cables when I set the amp up. Lou W1QJ, Rick K2XT, and Leon (call unknown) helped me get it sorted at Rick's house. The killer lunch was a bonus. I'd brought replacement caps for the HV supply, but Lou advised me against tinkering with it.

We also discovered that the transformer was not the right form factor for the unit. It's one of the "newer" units, s/n 465, and someone had hacked in a replacement transformer for one of the older ones. It's possible to get the transformer in and out without damaging the meters or the control board, but it''s tough. And whoever did it left metal filings in the case.

The amp is now home and put back together, and puts out about 200 watts for 5 watts input. Higher power level testing comes later.

73, -Steve WX2S

[N0XWR]

This is great news Steve.  Thanks for the update and thanks to Lou  and the guys for the help.  73, Jerry N0XWR