Repair broken Tek 485 or buy good used 2465/A/B?

[Jim Yanik]

[email protected] (David DiGiacomo) wrote in

Iwatsu still makes high performance analog scopes. They used to be
resold by LeCroy, but now I think you have to get them from Japan.

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.

 

[James Sweet]

See my original post:

"In the past, I have serviced tube amplifiers for friends. Right now I
have a 3M (Mincom) M56 professional
multitrack tape recorder I am currently in the process of aligning."

Probably going forward, much of the same.

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.

 

[[email protected]]

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...

 

[Jim Yanik]

[email protected] wrote in

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...

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.

 

[Bret Ludwig]

New scopes are expensive, used Teks in good working order are relatively
cheap and still offer excellent performance. There's millions of them out
there and parts units can still be found. If you're a business with budget
to burn then yes, buy a fancy new scope, but if you're a hobbyist on a
budget, you can't beat an old Tek.

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.

 

[Bret Ludwig]

There is only one problem: there are no "new scopes" that will
substitute for a 485/7904 for some purposes of work on analog signals.
Period. They don't exist.

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.

 

[Bret Ludwig]

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)...

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.

 

[JosephKK]

Michael A. Terrell [email protected] posted to
sci.electronics.equipment:

I agree 100%!!!!!!!! Buy a brand new chinese scope with no
support,
and throw it away when it dies. Repeat till you're tired of using
crap, then buy a used US made scope.

What US made scopes? Both Tek and HP moved their manufacturing to
Taiwan, Malaysia and China over a decade ago.