phase linear 400

gene french

gene french

Veteran and General Yakker
#523
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guayabo de bagaces, guanacaste, costa rica....
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music...the healer of souls...
#523
yes....but, it is the end of the dry seasons....basically weather is consistant year round, even amount of daylight, except for the rainfall....
no daylight savings here....
jan thru april is dry season...and it gets pretty dry by april....also the hottest month....
may thru december is wet season...
at times september and october can be memorable....in terms of water falling from the sky....chicken little was right after all...
before may 15...skies will darken....we have already got a sprinkle or two in april...just a prelude...
thanks for checking!!!!
 
ABebar

ABebar

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#527
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#527
I tore the whole thing apart down to the chassis. Cleaned up all of the solder joints. Checked all connections. Brought it up backplane only - all good. Added bottom driver transistors and brought it up - all good. Mounted and wired in the control board and just put the slightest voltage on and before I can get B+ to 2v my bias is already at 1v.
 
Gepetto

Gepetto

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Old 'Arn Enthusiast
#530
ABebar said:
I tore the whole thing apart down to the chassis. Cleaned up all of the solder joints. Checked all connections. Brought it up backplane only - all good. Added bottom driver transistors and brought it up - all good. Mounted and wired in the control board and just put the slightest voltage on and before I can get B+ to 2v my bias is already at 1v.
Click to expand...
Give us a few clues both channels or one channel only where the bias is climbing?

Have you jumpered the bias transistor C-E with a short piece of wire?
 
ABebar

ABebar

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#532
I was enjoying myself and listening to a new Clapton Crossroads 2019 vinyl box set that just showed up today. It sounds great. I highly recommend it. I was thinking I found enough questionable solder joints to feel fairly confident that I addressed the problem. Apparently it's somewhere else.
 
AngrySailor

AngrySailor

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---not quite right
#533
ABebar said:
I was enjoying myself and listening to a new Clapton Crossroads 2019 vinyl box set that just showed up today. It sounds great. I highly recommend it. I was thinking I found enough questionable solder joints to feel fairly confident that I addressed the problem. Apparently it's somewhere else.
Click to expand...
Hmmm I had bias issues with Tim (700/1 stock back planes and WO board) regarding bias. Ended up being an old back plane capacitor BUT I did notice that bias was wonky (if that’s a technical term) until the mains voltage came up a good bit. Now remember, Im a fookin rookie so ask the experts but if you’re bringing it up that slow that the front end can’t regulate bias, is that the issue? As in, you have NO issue but you’re pussy footing it? I used a 60w bulb and pretty much cranked the variac to 60v I think right off. I believe you said you went 10v. The DCP clicks around 80-90v if I recall. My bias was settling in there. Maybe try a low
Wattage bulb and just bang it 120v? The old “go big or go home”...???
 
gene french

gene french

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#539
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guayabo de bagaces, guanacaste, costa rica....
Tagline
music...the healer of souls...
#539
speaking for myself...no...takes at least 3 weeks for parts to get here...i reversed c8 on march 31...the parts will be here by next week at the latest...this is holy week in a catholic country...wednesday will be the last day this week that many will work until next monday...patience is a virtue..or so mom used to tell me...
 
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