snipped-for-privacy@slack.com (David DiGiacomo) wrote in news: snipped-for-privacy@corp.supernews.com:
how much "high performance" do you need for audio,tube amps?
250Mhz is overkill. A T922 (15Mhz)would suffice,and be far more reliable than a 485. No OOP TEK-made ICs,either.
Well using a 485 for that sort of work is sort of like using a McLaren F1 to go buy groceries. It'll do the job just fine, but there remains a huge amount of untapped capabilities.
That said, it'll do as fine a job as as anything else you can find, and as old as it is, the price should be reasonable.
Well, point being I already have the 485 which I got free from a friend who was hoping to use it but couldn't find the time over the years. But then it died shortly after I received it from him.
My original query was based more around the thought "Should I put money into this 485?". Or if it's too much hassle/cost to fix it would I be better served (on the repair person's advice) to sell/trade it in for a 2465 or another 485 he has (with the possible notion that I may "grow" into whatever I end up with)...
To which another poster in a cross-post has replied that it wouldn't be cost effective to repair the 485 implying that I could do the work myself...
snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@s8g2000prg.googlegroups.com:
the 485 power supply is a very tricky one;it's a series-resonant switcher with several control loops.it's very easy to make the PS -worse- than it was before you tried to fix it. It's also complicated by the terrible access to parts of the PS,and the inability to isolate scope circuit sections from the PS.
You definitely need a service manual before starting in on it.
Ante up and buy a brand new scope. Or a used refurbed late model in support one from a real supply house with a cal cert.
The old Teks are a bargain until the first unobtainable part fails. The problem is the same parts fail and therefore the supplies are exhausted. You wind up swapping out parts from a scope junkpile of carcasses you can't bear to chuck out since they are mostly good but one tiny weensy thing-okay, the jug isn't so tiny-and there are no more.
From a USER standpoint the best scopes ever made were the last analog Teks-22xx and 24xx B models with cursors, soft knobs, and "all mod cons" and a real electrostatically deflected CRT. From a repair standpoint they are a disaster. (There were also the aborted fetus TAS models which are dogshit even when working.)
The best analog scope tech TODAY, is far and away Iwatsu with their converter tube which is a small CRT with a CCD sensor in the end instead of phosphor screen. Their scopes are well made but the user interface is not as good as classic Teks.
New analog scope choices today come down to Iwatsu, Hameg, maybe Hitachi. Sencore still makes their overpriced shitbox and cheapo third tier models are available too.
The Lecroy people proved this false when they were selling Iwatsus here. The converter tube Iwatsu does everything a 485 does, but backwards and in high heels, plus gives you VGA and digital image storage.
If it can be fixed cheaply fine, but understand it's an asset that has a fixed and not well known finite life ahead of it. If the tube or any of half a dozen other things goes it's like, well, it's worse than an antique car with a shattered engine block-you can't swap in an incorrect but close looking engine. Tek made a cornucopia of CRTs each unique to one or two models.
Michael A. Terrell snipped-for-privacy@earthlink.net posted to sci.electronics.equipment:
What US made scopes? Both Tek and HP moved their manufacturing to Taiwan, Malaysia and China over a decade ago.
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