Topics

Type G plugin versions

cmjones01
 

For a while I've been looking for a differential amplifier plugin for my 535A scope. While I really want a Z, W or 1A5, I couldn't resist a type G plugin at a great price locally. It was missing a knob and one valve but otherwise in great shape.

While getting it working, I've found that it's very different from what's documented in the manual available on TekWiki for the 53/54G. My plugin contains four 12AU6s, two 6AK5s and a 12AT7, as do the ones in the photos on TekWiki. The schematic in the manual, however, has two 12AU6s and three 12AT7s. The front panels are the same, though.

http://w140.com/tekwiki/wiki/G

What's going on here? Were there two versions of the plugin? I'd like to find the right manual for the plugin I've got.

Thanks
Chris

Jerry Ingordo
 

Hi Chris.
You have an early G plugin. Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual. Log in is simple, create a screen name and password and your in. There may be a waiting period for new users to download. If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

cmjones01
 

Jerry,

Thank you very much for the pointer. That manual matches what I've got. A replacement 12AU6 (most of the vacuum has escaped from one of the ones in the plugin) has just arrived so I'll see if I can get it working.

Regards
Chris

Dave Wise
 

Chris's manual is for the 53G (12AU6x2, 12AT7x2, 12AT7), while his plugin is the later, faster G (6AK5x2, 12AU6x2, 12AU6x2, 12AT7). I edited the wiki page to mention that 53G has five tubes while G has seven.

Regards,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jerry Ingordo <gjingordo@...>
Sent: Wednesday, October 24, 2018 3:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Hi Chris.
You have an early G plugin. Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual. Log in is simple, create a screen name and password and your in. There may be a waiting period for new users to download. If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

Dave Seiter
 

My G (serial number just under 10K) has holes in the front panel for the original connectors, but is loaded with BNCs which look factory installed.  Anyone know when this transition took place?
-Dave

From: Dave Wise <david_wise@...>
To: "TekScopes@groups.io" <TekScopes@groups.io>
Sent: Wednesday, October 24, 2018 7:32 AM
Subject: Re: [TekScopes] Type G plugin versions

Chris's manual is for the 53G (12AU6x2, 12AT7x2, 12AT7), while his plugin is the later, faster G (6AK5x2, 12AU6x2, 12AU6x2, 12AT7).  I edited the wiki page to mention that 53G has five tubes while G has seven.

Regards,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Jerry Ingordo <gjingordo@...>
Sent: Wednesday, October 24, 2018 3:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Hi Chris.
You have an early G plugin.  Here is a link to the early manual.

http://ebaman.com/index.php/remository/func-startdown/22331/

You have to log in to download the manual.  Log in is simple, create a screen name and password and your in.  There may be a waiting period for new users to download.  If you have a problem getting the manual contact me and I'll get a copy to you.

Jerry
W2JI

cmjones01
 

On Wed, Oct 24, 2018 at 06:16 AM, cmjones01 wrote:
Thank you very much for the pointer. That manual matches what I've got. A
replacement 12AU6 (most of the vacuum has escaped from one of the ones in the
plugin) has just arrived so I'll see if I can get it working.
Replacement 12AU6 installed in addition to a substitute for the missing 6AK5, adjustments to gain, DC balance and vertical position range as expected, plugin now seems to work perfectly. That wasn't too hard!

Chris

cmjones01
 

On Wed, Oct 24, 2018 at 10:21 AM, Dave Seiter wrote:
My G (serial number just under 10K) has holes in the front panel for the
original connectors, but is loaded with BNCs which look factory installed. 
Anyone know when this transition took place?
My G also has BNC connectors. If it's anything like the other 500 series equipment, I think the transition was in the mid-to-late 1960s. My 535A has factory-fitted BNCs as well.

Chris

Dave Wise
 

I don't know the G serial number at which Tek switched from UHF to BNC*, but the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least one modded scope and plugin. Yours too, most likely, as Tek would not have sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of cmjones01 <chris@...>
Sent: Wednesday, October 24, 2018 11:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

On Wed, Oct 24, 2018 at 10:21 AM, Dave Seiter wrote:
My G (serial number just under 10K) has holes in the front panel for the
original connectors, but is loaded with BNCs which look factory installed.
Anyone know when this transition took place?
My G also has BNC connectors. If it's anything like the other 500 series equipment, I think the transition was in the mid-to-late 1960s. My 535A has factory-fitted BNCs as well.

Chris

Albert Otten
 

According to the later manual Type G switched from UHF (131-012) to BNC (131-277) at S/N 9480. No idea in which year that was.
Albert

On Thu, Oct 25, 2018 at 08:17 PM, Dave Wise wrote:


I don't know the G serial number at which Tek switched from UHF to BNC*, but
the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual
at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least
one modded scope and plugin. Yours too, most likely, as Tek would not have
sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.

cmjones01
 

On Thu, Oct 25, 2018 at 12:44 PM, Albert Otten wrote:
According to the later manual Type G switched from UHF (131-012) to BNC
(131-277) at S/N 9480. No idea in which year that was.
My 535A and G are Guernsey-built. The 535A is s/n 101936, and the G is s/n 101127. They both have BNCs which look like they were factory-fitted, though they are of the special Tek type with enlarged flanges to fit the UHF connector hole.

Chris

Dave Wise
 

I was partly wrong. Tek retooled the front panel for BNC, but not until 1967. From 1963 through 1966, they used the UHF front panel with a square-flange BNC jack and plastic trim covering the annular gap. The letter-series plugins built this way are CA, D, G, and L. Others like the K were retooled immediately, if the catalogs are right.

I have plugins of each construction. One of my scopes, a 545, was definitely field-modded, since it was built in the 1950's. It doesn't have the trim and it looks a bit awkward without it.

Beaverton 535A switched to BNC at 31260, but that doesn't tell us anything about Guernsey.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of cmjones01 <chris@...>
Sent: Thursday, October 25, 2018 1:27 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

On Thu, Oct 25, 2018 at 12:44 PM, Albert Otten wrote:
According to the later manual Type G switched from UHF (131-012) to BNC
(131-277) at S/N 9480. No idea in which year that was.
My 535A and G are Guernsey-built. The 535A is s/n 101936, and the G is s/n 101127. They both have BNCs which look like they were factory-fitted, though they are of the special Tek type with enlarged flanges to fit the UHF connector hole.

Chris

Dave Seiter
 

Wow- my G is s/s 9934, so it's just after the change.  Strange that they didn't change the sheet metal right away.
-Dave

From: Albert Otten <aodiversen@...>
To: TekScopes@groups.io
Sent: Thursday, October 25, 2018 12:44 PM
Subject: Re: [TekScopes] Type G plugin versions

According to the later manual Type G switched from UHF (131-012) to BNC (131-277) at S/N 9480. No idea in which year that was.
Albert

On Thu, Oct 25, 2018 at 08:17 PM, Dave Wise wrote:


I don't know the G serial number at which Tek switched from UHF to BNC*, but
the 1962 catalog shows UHF while 1963 is BNC**.  I think I have a newer manual
at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field.  I have at least
one modded scope and plugin.  Yours too, most likely, as Tek would not have
sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.

Dave Wise
 

Further study of the catalogs suggests that they never did retool. In 1967, some instruments with plastic trim went "limited demand" without pictures; others simply dropped the trim. As far as I can tell, the hole stayed the same size. It's possible that the BNC was switched from square four-screw mount to round flange and single large rear retention nut. If I remember to, I will study my plugins when I'm at home this weekend.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Seiter <d.seiter@...>
Sent: Friday, October 26, 2018 12:17 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Wow- my G is s/s 9934, so it's just after the change. Strange that they didn't change the sheet metal right away.
-Dave

From: Albert Otten <aodiversen@...>
To: TekScopes@groups.io
Sent: Thursday, October 25, 2018 12:44 PM
Subject: Re: [TekScopes] Type G plugin versions

According to the later manual Type G switched from UHF (131-012) to BNC (131-277) at S/N 9480. No idea in which year that was.
Albert

On Thu, Oct 25, 2018 at 08:17 PM, Dave Wise wrote:


I don't know the G serial number at which Tek switched from UHF to BNC*, but
the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual
at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least
one modded scope and plugin. Yours too, most likely, as Tek would not have
sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.

Dave Wise
 

It's as I thought.

Instruments built before 1963 had UHF connectors. The connector has a square flange secured to the back side of the bulkhead.

For 1963 production of the old instruments, they replaced the UHF connector with a BNC with the same square flange, and they didn't change the front panel or the bulkhead. They added a plastic trim ring to conceal the annular gap. (The ring is missing from my Type L plugin.)

For 1967 production of the old instruments, they retooled the bulkhead. The new connector mounts from the front instead of the rear. It's retained by a large round flange in the front, and secured by a ring nut in the rear. The flange makes a smooth visual transition to the large hole in the old UHF-style front panel.

Instruments introduced in 1963 and later had front-installed connectors with small round flange, and matching front panels.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Wise <david_wise@...>
Sent: Friday, October 26, 2018 9:04 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Further study of the catalogs suggests that they never did retool. In 1967, some instruments with plastic trim went "limited demand" without pictures; others simply dropped the trim. As far as I can tell, the hole stayed the same size. It's possible that the BNC was switched from square four-screw mount to round flange and single large rear retention nut. If I remember to, I will study my plugins when I'm at home this weekend.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Dave Seiter <d.seiter@...>
Sent: Friday, October 26, 2018 12:17 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Type G plugin versions

Wow- my G is s/s 9934, so it's just after the change. Strange that they didn't change the sheet metal right away.
-Dave

From: Albert Otten <aodiversen@...>
To: TekScopes@groups.io
Sent: Thursday, October 25, 2018 12:44 PM
Subject: Re: [TekScopes] Type G plugin versions

According to the later manual Type G switched from UHF (131-012) to BNC (131-277) at S/N 9480. No idea in which year that was.
Albert

On Thu, Oct 25, 2018 at 08:17 PM, Dave Wise wrote:


I don't know the G serial number at which Tek switched from UHF to BNC*, but
the 1962 catalog shows UHF while 1963 is BNC**. I think I have a newer manual
at home, I'll try to remember to look.

There was a mod kit for converting instruments in the field. I have at least
one modded scope and plugin. Yours too, most likely, as Tek would not have
sold instruments with such an obvious bodge.

Dave Wise

* For what it's worth, the 535A mainframe switched at 31260.
** Some old models were not updated.