I have *no* experience in this domain, so I am unable to offer advice. However, I have a Yaesu FT-101E and a Kenwood TS-520 in queue for functional restoration for sentimental reasons both of which are hybrids with tube finals. So I shall be paying close attention to the discussion.
The *only* contribution I might be able to make is generic WW II era parts that my Dad left me. If, for example, someone finds an HRO in need of a tuning capacitor I have several NOS HW-4s. Those were $30 list in 1942 per the handbook catalog. That was a week's wages for the people who made them. As those are about as pure unobtainium as it gets I shall be very picky about whom I sell them to, and it will probably be more than $30. Price based solely on my assessment of the buyer. Free to "RF Gods". but it will take a strong publication record in QST to rate that status. To the best of my knowledge, those are the finest air variables *ever* made on a production basis.
Have Fun!
Reg
On Friday, January 19, 2024 at 08:57:27 PM CST, gren <hrgerson@...> wrote:
Hoping to stimulate some discussion on Old Ham Tube Linear Amps:
? Are there any experienced with the various Tube Amp issues,
???? ... such as Arcing and Band SW,? coil,? capacitor & tube and HV Xfrmr destruction in these amplifiers ?
I am beginning to refurbish two old Heathkit Linear Amps:
?? the SB-1000? ( similar to the AL-80)?
& the SB-200.
? Scouring the Web looking for information on refurbishing issues and modifying old Heathkit Ham Linear Tube amplifiers
quick summary:
PS Cap board
Metering board /Bias
Soft-Key
Soft-Start
Parasitic's
Glitch resistor
HEC HV Caps
Self-biasing of relays
"Corona Washer "
QSK
new tubes ...
poor solder joints (expected)
Band Sw issues,
etc.
There are plenty of Ham Blogs on the SB-200? & SB-220,? ...? but fewer on the SB-1000 & HL-2200.
?Articles by Richard Measures, and others, some with theory, discussion, diagrams, photos ,
??? and, as with anything,? some miss-information and some corrections.
There are a lot of YouTube videos,? and ? AmpRepairGuy.com?? has some videos of his repairs.
? Likely others , all requiring sifting the information and reasoning.
Harbach Co.? & CTR Engineering? Kits,? parts for? Mods (depending on the Amp Model):
? Having good instruction,? kits, ? PCB's ?? and downloadable .pdf's at both of these? two? web sites:
Possibly the Richard Measures (SK) Amp Forum, has some priceless,? sometimes buried help:
The "search" bar? { below }? can still dial in the query:
example:
And,
? ....? there seem to be some PCB's? from?? W7RY , although I have not been successful getting adequate answers or actually purchasing the PCB's
thanks,
