How to ruin a 535...


Albert LaFrance <lafrance@...>
 


Miroslav Pokorni
 

I am sorry to say, but this is not the first one, neither it will be the
last one, ruined that way. The 585 that I have, was a working scope and a
guy pulled out all ECC81 and gave me the remainder, even helped me to load
it into car.

What can I say, not everyone appriciates those old scopes.

Regards

Miroslav Pokorni

----- Original Message -----
From: "Albert LaFrance" <lafrance@att.net>
To: "TekScopes" <TekScopes@yahoogroups.com>
Sent: Wednesday, January 21, 2004 8:08 AM
Subject: [TekScopes] How to ruin a 535...


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2590535177

Albert




Craig Sawyers <c.sawyers@...>
 

I am sorry to say, but this is not the first one, neither it will be the
last one, ruined that way.
Yup. I've seen a few on eBay sans tubes over the last year. Suppose the
equation is that the 18 or more 6DJ8's are worth a mint to the audio folks
(perhaps $20 each), whereas a fully working 5xx series scope will only get
$50 maximum.

Very glad that my 545A has the full complement of firebottles!

Craig


oldtek2003
 

--- In TekScopes@yahoogroups.com, "Craig Sawyers" <c.sawyers@t...>
wrote:

I bought a scope on eBay which had all the 6BQ7A's replaced with
6DJ8 - the Amperex "Orange Globe" variety - which from my cursory
research, seem to be fetching a premium on eBay. Can't understand
it myself... but anyway, it looks like there's some money to be made
here. I'll pull all the 6DJ8s and replace them with some JAN
6BQ7A's that I bought for next to nothing, and sell the 6DJ8's to
some audiophile nutter... that should cover my original investment
in the scope and repair parts (and repair parts for the next 40
years).

Cheers,
Tony


Yup. I've seen a few on eBay sans tubes over the last year.
Suppose the
equation is that the 18 or more 6DJ8's are worth a mint to the
audio folks
(perhaps $20 each), whereas a fully working 5xx series scope will
only get
$50 maximum.

Very glad that my 545A has the full complement of firebottles!

Craig


Bill Lewis <wrljet@...>
 

I got my 180A like that. Only had to dig up the 52 tubes to put it back on the air.

Had a few others like that as well.

Bill

From: "Albert LaFrance" <lafrance@att.net>

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2590535177

Albert


Robert Morein <morepub@...>
 

If you do that, you should know that the 6BQ7A may have been an older tube that had a mechanically fragile structure. Simply moving the scope around could cause tube failure. The later "frame grid" tubes were an advance in shock resistance.

I can't remember for sure whether the 6BQ7A is the problem tube, but I encountered this with a 545.

----- Original Message -----
From: Tony Denning
To: TekScopes@yahoogroups.com
Sent: Wednesday, January 21, 2004 8:16 PM
Subject: [TekScopes] Re: How to ruin a 535...


--- In TekScopes@yahoogroups.com, "Craig Sawyers" <c.sawyers@t...>
wrote:

I bought a scope on eBay which had all the 6BQ7A's replaced with
6DJ8 - the Amperex "Orange Globe" variety - which from my cursory
research, seem to be fetching a premium on eBay. Can't understand
it myself... but anyway, it looks like there's some money to be made
here. I'll pull all the 6DJ8s and replace them with some JAN
6BQ7A's that I bought for next to nothing, and sell the 6DJ8's to
some audiophile nutter... that should cover my original investment
in the scope and repair parts (and repair parts for the next 40
years).

Cheers,
Tony


>> Yup. I've seen a few on eBay sans tubes over the last year.
Suppose the
> equation is that the 18 or more 6DJ8's are worth a mint to the
audio folks
> (perhaps $20 each), whereas a fully working 5xx series scope will
only get
> $50 maximum.
>
> Very glad that my 545A has the full complement of firebottles!
>
> Craig



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oldtek2003
 

---
Interesting. I wasn't aware of this with 6BQ7A's From the manuals &
schematics I've seen, it looks like Tektronix did away with 6BQ7A's
around 1958-59, replacing them with 6DJ8s, which from my recollection
have a higher Gm. The 6BQ7A's I have are military surplus, made by
GE in the early 60's. I haven't had any problem with them as of yet.
Perhaps the older 6BQ7 had the problem.

Tony


In TekScopes@yahoogroups.com, "Robert Morein" <morepub@c...> wrote:
If you do that, you should know that the 6BQ7A may have been an
older tube that had a mechanically fragile structure. Simply moving
the scope around could cause tube failure. The later "frame grid"
tubes were an advance in shock resistance.

I can't remember for sure whether the 6BQ7A is the problem tube,
but I encountered this with a 545.

I bought a scope on eBay which had all the 6BQ7A's replaced with
6DJ8 - the Amperex "Orange Globe" variety - which from my cursory
research, seem to be fetching a premium on eBay. Can't
understand
it myself... but anyway, it looks like there's some money to be
made
here. I'll pull all the 6DJ8s and replace them with some JAN
6BQ7A's that I bought for next to nothing, and sell the 6DJ8's to
some audiophile nutter... that should cover my original
investment
in the scope and repair parts (and repair parts for the next 40
years).


Dave Wise
 

6DJ8s were allowed (nay, preferred) as a substitute
for the 6BQ7A in the 53x/54x. The reason given in
the Mod Summary: Reliability.

'nuff said.

Dave Wise

-----Original Message-----
From: Tony Denning [mailto:tdenning@sympatico.ca]
Sent: Thursday, January 22, 2004 9:37 AM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] Re: How to ruin a 535...


---
Interesting. I wasn't aware of this with 6BQ7A's From the manuals &
schematics I've seen, it looks like Tektronix did away with 6BQ7A's
around 1958-59, replacing them with 6DJ8s, which from my recollection
have a higher Gm. The 6BQ7A's I have are military surplus, made by
GE in the early 60's. I haven't had any problem with them as of yet.
Perhaps the older 6BQ7 had the problem.

Tony


In TekScopes@yahoogroups.com, "Robert Morein" <morepub@c...> wrote:
If you do that, you should know that the 6BQ7A may have been an
older tube that had a mechanically fragile structure. Simply moving
the scope around could cause tube failure. The later "frame grid"
tubes were an advance in shock resistance.

I can't remember for sure whether the 6BQ7A is the problem tube,
but I encountered this with a 545.

I bought a scope on eBay which had all the 6BQ7A's replaced with
6DJ8 - the Amperex "Orange Globe" variety - which from my cursory
research, seem to be fetching a premium on eBay. Can't
understand
it myself... but anyway, it looks like there's some money to be
made
here. I'll pull all the 6DJ8s and replace them with some JAN
6BQ7A's that I bought for next to nothing, and sell the 6DJ8's to
some audiophile nutter... that should cover my original
investment
in the scope and repair parts (and repair parts for the next 40
years).




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