Topics

Unusual TM5xx(x) MF - its not a TM500 or a TM5000

 

For several years I have been aware that there are some unusual TM 5xx(x)
Main Frame power supplies floating around that look, at first glance like a
newer model TM502 or TM503 but they have GPIB connectors in them which only
a TM5003 or TM5006 would have. In addition there is another distinguishing
feature to help spot that this is not a TM5003: a TM5003 has a 1" high
plenum with a grille on the front of the MF under the three slots. This MF
does not have a plenum.

The three wide MF has an additional barrier strip in the center connector to
prevent a common TM500 plugin from being inserted in it. The other slot(s)
will accept regular TM500 plugins. I have two of these unusual 3 wide MFs.
An easy way to distinguish them is the unusual adjustable handle which lets
you position the MF in many different positions on a desk.

These MFs were introduced by Tek to allow some of their GPIB equipped TM5000
plugins to be operated as stand-alone instruments. Ones that I am aware of
are:

AFG 5501 (AFG 5101 in a three wide MF)

AM 503S (AM 503 and 016-0362-02 Tool Box in a two wide MF), also known as AM
5030

DM 5520 (DM 5120 in a three wide MF)

PFG 5505 (PFG 5105 in a three wide MF)

There may be more.



I finally got around to opening one of these 3 wide units up and I was very
surprised at what I saw. It is extremely sparse. It appears the Tek
engineers have reduced this design down to a bare minimum number of parts.
There is a transformer (not an SMPS) and a backplane, a few wires and
connectors, 6 pass transistors and little else.

The backplane has a part number on it and I am hoping someone can supply a
schematic for it although I don't think it is too much different from a
TM503. The backplane is marked RA-9804-00 POWER SUPPLY (C) 1988.

There are three filter capacitors on the backplane 22,000uF/16V,
4,700uF/50V, and 4,700uF/50V. The backplane has three TM503 connectors and
three GPIB connectors and two pass transistors for each slot.

I couldn't measure the pass transistors to confirm there is a PNP and an NPN
for each slot but that is a safe assumption. One of the pass transistors for
the middle slot appears to be connected to a 9V Zener Diode which appears to
force it to be a simple 10V regulator. That is probably why there is a
barrier strip in the middle slot between positions 27 and 28. I did not see
any reason the back plane couldn't be modified to remove the simple
regulator and rewire the pass transistor to be like any other TM503.



Dennis Tillman W7PF

bobh@joba.com
 

Aren't these referred to as TM502A, TM503A, etc?  I have a TM503A and it also does not have a fan of course since it doesn't have the space in the bottom, as you mentioned, for air flow.

Bob.

On 4/9/2019 12:08 AM, Dennis Tillman W7PF wrote:
For several years I have been aware that there are some unusual TM 5xx(x)
Main Frame power supplies floating around that look, at first glance like a
newer model TM502 or TM503 but they have GPIB connectors in them which only
a TM5003 or TM5006 would have. In addition there is another distinguishing
feature to help spot that this is not a TM5003: a TM5003 has a 1" high
plenum with a grille on the front of the MF under the three slots. This MF
does not have a plenum.

The three wide MF has an additional barrier strip in the center connector to
prevent a common TM500 plugin from being inserted in it. The other slot(s)
will accept regular TM500 plugins. I have two of these unusual 3 wide MFs.
An easy way to distinguish them is the unusual adjustable handle which lets
you position the MF in many different positions on a desk.

These MFs were introduced by Tek to allow some of their GPIB equipped TM5000
plugins to be operated as stand-alone instruments. Ones that I am aware of
are:

AFG 5501 (AFG 5101 in a three wide MF)

AM 503S (AM 503 and 016-0362-02 Tool Box in a two wide MF), also known as AM
5030

DM 5520 (DM 5120 in a three wide MF)

PFG 5505 (PFG 5105 in a three wide MF)

There may be more.


I finally got around to opening one of these 3 wide units up and I was very
surprised at what I saw. It is extremely sparse. It appears the Tek
engineers have reduced this design down to a bare minimum number of parts.
There is a transformer (not an SMPS) and a backplane, a few wires and
connectors, 6 pass transistors and little else.

The backplane has a part number on it and I am hoping someone can supply a
schematic for it although I don't think it is too much different from a
TM503. The backplane is marked RA-9804-00 POWER SUPPLY (C) 1988.

There are three filter capacitors on the backplane 22,000uF/16V,
4,700uF/50V, and 4,700uF/50V. The backplane has three TM503 connectors and
three GPIB connectors and two pass transistors for each slot.

I couldn't measure the pass transistors to confirm there is a PNP and an NPN
for each slot but that is a safe assumption. One of the pass transistors for
the middle slot appears to be connected to a 9V Zener Diode which appears to
force it to be a simple 10V regulator. That is probably why there is a
barrier strip in the middle slot between positions 27 and 28. I did not see
any reason the back plane couldn't be modified to remove the simple
regulator and rewire the pass transistor to be like any other TM503.


Dennis Tillman W7PF



Hawker
 

I wonder if that is different than the A series?
I have a TM504A. AFAIK the 504A is a 504 beefed up (bigger caps and pass transistors) and fan specifically designed for the audio distortion analyzer and signal generator plug ins. It has a fan but does not have the lower venting.of the TM5000x series. It also does not have GPIB as the OP mentioned. It is not a 5000x series but a 500 series main frame. It does look more modern than a TM504 but not as modern as a 5000 series or as tall.

The funny thing about the TM504A is, although it was designed for Audio plug ins, the fan is so crazy noisy I can't stand to use it. I did replace it with a lower noise fan, with the same air flow, but it is still really noisy and I can't stand to use it unless I have to due to this.

 

On Tue, Apr 9, 2019 at 09:08 AM, Dennis Tillman W7PF wrote:


AM 503S (AM 503 and 016-0362-02 Tool Box in a two wide MF), also known as AM5030
AM503S was, depending of the year, an AM503, AM503A or an AM503B with an A6302 current probe
and the tool box in a standard TM502A . AM5030 was the TM5000 version of an AM503B, i.e.
an AM503B with a GPIB board.

/Håkan

 

Hi Bob,
It would be very misleading if these unusual hybrids were referred to as TM502A, TM503A, etc.
There is a TM502A (I have two) and it is nothing but an updated version of a TM502. It is clearly marked at the front as a TM502A. There are no special wirings of either slot that would prevent any TM500 plugin from working properly. There is no additional barrier that would prevent any TM500 plugin from being used in either slot.
I don't have a TM503A (if one exists) so I can't say how that differs from a TM503 but it would have to have three fully functional slots and no additional barriers or a rewired pass transistor dedicated as a regulated power supply for the middle slot.
This unusual three wide mainframe I am describing has NO MARKINGS on it to indicate what it is. Apparently Tek avoided the question entirely of what exactly it is by not saying anything at all. I do have an AM503 that came from an AM503S stand-alone instrument that I described in my previous email. It is just an ordinary AM503 but it has THREE labels on it. The first label, which is in the usual place, is the original serial number it was given: B086364. The next label says IDENTIFICATION and it lists this plugin as AM503S. The last label is another serial number (presumably for the entire stand-alone AM 503S instrument package and it is: B013019.
Dennis Tillman W7PF

-----Original Message-----
From: bobh@...
Sent: Tuesday, April 09, 2019 5:06 AM
Subject: Re: [TekScopes] Unusual TM5xx(x) MF - its not a TM500 or a
TM5000

Aren't these referred to as TM502A, TM503A, etc? I have a TM503A and
it also does not have a fan of course since it doesn't have the space
in the bottom, as you mentioned, for air flow.

Bob.

On 4/9/2019 12:08 AM, Dennis Tillman W7PF wrote:
For several years I have been aware that there are some unusual TM
5xx(x) Main Frame power supplies floating around that look, at first
glance like a newer model TM502 or TM503 but they have GPIB
connectors
in them which only a TM5003 or TM5006 would have. In addition there
is
another distinguishing feature to help spot that this is not a
TM5003:
a TM5003 has a 1" high plenum with a grille on the front of the MF
under the three slots. This MF does not have a plenum.

The three wide MF has an additional barrier strip in the center
connector to prevent a common TM500 plugin from being inserted in
it.
The other slot(s) will accept regular TM500 plugins. I have two of
these unusual 3 wide MFs.
An easy way to distinguish them is the unusual adjustable handle
which
lets you position the MF in many different positions on a desk.

These MFs were introduced by Tek to allow some of their GPIB
equipped
TM5000 plugins to be operated as stand-alone instruments. Ones that
I
am aware of
are:

AFG 5501 (AFG 5101 in a three wide MF)
AM 503S (AM 503 and 016-0362-02 Tool Box in a two wide MF),
also known as AM 5030
DM 5520 (DM 5120 in a three wide MF)
PFG 5505 (PFG 5105 in a three wide MF)
There may be more.

I finally got around to opening one of these 3 wide units up and I
was
very surprised at what I saw. It is extremely sparse. It appears the
Tek engineers have reduced this design down to a bare minimum number
of parts.
There is a transformer (not an SMPS) and a backplane, a few wires
and
connectors, 6 pass transistors and little else.

The backplane has a part number on it and I am hoping someone can
supply a schematic for it although I don't think it is too much
different from a TM503. The backplane is marked RA-9804-00 POWER
SUPPLY (C) 1988.

There are three filter capacitors on the backplane 22,000uF/16V,
4,700uF/50V, and 4,700uF/50V. The backplane has three TM503
connectors
and three GPIB connectors and two pass transistors for each slot.

I couldn't measure the pass transistors to confirm there is a PNP
and
an NPN for each slot but that is a safe assumption. One of the pass
transistors for the middle slot appears to be connected to a 9V
Zener
Diode which appears to force it to be a simple 10V regulator. That
is
probably why there is a barrier strip in the middle slot between
positions 27 and 28. I did not see any reason the back plane
couldn't
be modified to remove the simple regulator and rewire the pass
transistor to be like any other TM503.
Dennis Tillman W7PF



--
Dennis Tillman W7PF
TekScopes Moderator

 

Hi Hawker,
How do you know the TM504A was designed for audio work??? This is the first I heard of this special adaptation. Is this an option listed in the catalogs? Does it say that in the service manual somewhere?I also have a newer TM500 MF. Mine is a 6 slot MF. It looks exactly like a TM5006 on the front due to the color scheme and the plenum below the MF. It says TM506A in exactly the same place the TM5006 label would be. I thought I was buying a TM5006 until I got it home and noticed there were no GPIB connectors. Even now with the TM506A in a stack of three TM5006s I can't tell which one is the TM506A unless I look carefully at the label on the front.
The TM500 and TM5000 MF fans are a source of numerous noise complaints. About 1/4 of my TM mainframes have fans that cause me to grit my teeth when I turn them on. But when I think about the hassle of replacing them I quickly chose to accept the noise because if I was going to replace one of then I would probably choose to replace them all. I have 15 TM506 or TM5006 so that would be way too much work.
Dennis Tillman W7PF

-----Original Message-----
From: Hawker
Sent: Tuesday, April 09, 2019 10:21 AM
Subject: Re: [TekScopes] Unusual TM5xx(x) MF - its not a TM500 or a
TM5000

I wonder if that is different than the A series?
I have a TM504A. AFAIK the 504A is a 504 beefed up (bigger caps and
pass transistors) and fan specifically designed for the audio
distortion analyzer and signal generator plug ins. It has a fan but
does not have the lower venting.of the TM5000x series. It also does
not have GPIB as the OP mentioned. It is not a 5000x series but a 500
series main frame. It does look more modern than a TM504 but not as
modern as a 5000 series or as tall.

The funny thing about the TM504A is, although it was designed for
Audio plug ins, the fan is so crazy noisy I can't stand to use it. I
did replace it with a lower noise fan, with the same air flow, but it
is still really noisy and I can't stand to use it unless I have to due
to this.


--
Dennis Tillman W7PF
TekScopes Moderator

Chuck Harris
 

I do have a TM503A, and it is pretty close to the
TM503 in design, only simpler.

Switch is on the back panel,
IEC power connector,
No side handle,
Round spool type feet on the back for winding the cord.
No 50 pin D style connector on the back

My 503A spends all of its time on a shelf, not being used
in preference for the front power switch 503's.

-Chuck Harris

Dennis Tillman W7PF wrote:

Hi Bob,
It would be very misleading if these unusual hybrids were referred to as TM502A, TM503A, etc.
There is a TM502A (I have two) and it is nothing but an updated version of a TM502. It is clearly marked at the front as a TM502A. There are no special wirings of either slot that would prevent any TM500 plugin from working properly. There is no additional barrier that would prevent any TM500 plugin from being used in either slot.
I don't have a TM503A (if one exists) so I can't say how that differs from a TM503 but it would have to have three fully functional slots and no additional barriers or a rewired pass transistor dedicated as a regulated power supply for the middle slot.
This unusual three wide mainframe I am describing has NO MARKINGS on it to indicate what it is. Apparently Tek avoided the question entirely of what exactly it is by not saying anything at all. I do have an AM503 that came from an AM503S stand-alone instrument that I described in my previous email. It is just an ordinary AM503 but it has THREE labels on it. The first label, which is in the usual place, is the original serial number it was given: B086364. The next label says IDENTIFICATION and it lists this plugin as AM503S. The last label is another serial number (presumably for the entire stand-alone AM 503S instrument package and it is: B013019.
Dennis Tillman W7PF

J Mcvein
 

I had a 3-slot special built for a optical fiber test set thattek built. (OPC-nnn)?  The center slot was wired different.  I
had to cut some traces and add a pass transistor.  The raw 11Vwas regulated to 9V.  None of the regular TM-500's seemed to mindthe 9V, but if you removed the key and put one in the center slot,it would smoke if the backplane was not modified.
To fit TM-5000's, I had to mill slots in the outer housing to
accept the keys on top of the modules.There was not a model ID where one would usually go on the topof the housing.
JimMc

On Tuesday, April 9, 2019, 1:14:01 PM PDT, Dennis Tillman W7PF <@Dennis_Tillman_W7PF> wrote:

Hi Bob,
It would be very misleading if these unusual hybrids were referred to as TM502A, TM503A, etc.
There is a TM502A (I have two) and it is nothing but an updated version of a TM502. It is clearly marked at the front as a TM502A. There are no special wirings of either slot that would prevent any TM500 plugin from working properly. There is no additional barrier that would prevent any TM500 plugin from being used in either slot.
I don't have a TM503A (if one exists) so I can't say how that differs from a TM503 but it would have to have three fully functional slots and no additional barriers or a rewired pass transistor dedicated as a regulated power supply for the middle slot.
This unusual three wide mainframe I am describing has NO MARKINGS on it to indicate what it is. Apparently Tek avoided the question entirely of what exactly it is by not saying anything at all. I do have an AM503 that came from an AM503S stand-alone instrument that I described in my previous email. It is just an ordinary AM503 but it has THREE labels on it. The first label, which is in the usual place, is the original serial number it was given: B086364. The next label says IDENTIFICATION and it lists this plugin as AM503S. The last label is another serial number (presumably for the entire stand-alone AM 503S instrument package and it is: B013019.
Dennis Tillman W7PF

-----Original Message-----
From: bobh@...
Sent: Tuesday, April 09, 2019 5:06 AM
Subject: Re: [TekScopes] Unusual TM5xx(x) MF - its not a TM500 or a
TM5000

Aren't these referred to as TM502A, TM503A, etc?  I have a TM503A and
it also does not have a fan of course since it doesn't have the space
in the bottom, as you mentioned, for air flow.

Bob.

On 4/9/2019 12:08 AM, Dennis Tillman W7PF wrote:
For several years I have been aware that there are some unusual TM
5xx(x) Main Frame power supplies floating around that look, at first
glance like a newer model TM502 or TM503 but they have GPIB
connectors
in them which only a TM5003 or TM5006 would have. In addition there
is
another distinguishing feature to help spot that this is not a
TM5003:
a TM5003 has a 1" high plenum with a grille on the front of the MF
under the three slots. This MF does not have a plenum.

The three wide MF has an additional barrier strip in the center
connector to prevent a common TM500 plugin from being inserted in
it.
The other slot(s) will accept regular TM500 plugins. I have two of
these unusual 3 wide MFs.
An easy way to distinguish them is the unusual adjustable handle
which
lets you position the MF in many different positions on a desk.

These MFs were introduced by Tek to allow some of their GPIB
equipped
TM5000 plugins to be operated as stand-alone instruments. Ones that
I
am aware of
are:

AFG 5501 (AFG 5101 in a three wide MF)
AM 503S (AM 503 and 016-0362-02 Tool Box in a two wide MF),
also known as AM 5030
DM 5520 (DM 5120 in a three wide MF)
PFG 5505 (PFG 5105 in a three wide MF)
There may be more.

I finally got around to opening one of these 3 wide units up and I
was
very surprised at what I saw. It is extremely sparse. It appears the
Tek engineers have reduced this design down to a bare minimum number
of parts.
There is a transformer (not an SMPS) and a backplane, a few wires
and
connectors, 6 pass transistors and little else.

The backplane has a part number on it and I am hoping someone can
supply a schematic for it although I don't think it is too much
different from a TM503. The backplane is marked RA-9804-00 POWER
SUPPLY (C) 1988.

There are three filter capacitors on the backplane 22,000uF/16V,
4,700uF/50V, and 4,700uF/50V. The backplane has three TM503
connectors
and three GPIB connectors and two pass transistors for each slot.

I couldn't measure the pass transistors to confirm there is a PNP
and
an NPN for each slot but that is a safe assumption. One of the pass
transistors for the middle slot appears to be connected to a 9V
Zener
Diode which appears to force it to be a simple 10V regulator. That
is
probably why there is a barrier strip in the middle slot between
positions 27 and 28. I did not see any reason the back plane
couldn't
be modified to remove the simple regulator and rewire the pass
transistor to be like any other TM503.
Dennis Tillman W7PF



--
Dennis Tillman W7PF
TekScopes Moderator

John Mullens
 

All,
I've had several of these from various acquisitions. One of them - a -B - apparently supports any plugin in any slot. The others were keyed or had block-off plates installed so they could be used only with their accompanying plugin. This one also has full GPIB support in all slots.

...John...

 

Hi Chuck,
Thanks for the info on the TM503A.

Where to put the power switch is an interesting issue. I'll bet it was a heated discussion at Tek.
You and I and others who use our TM mainframes on a bench want the switch on the front of the mainframe so we can turn it on when we need it.

But when a TM503 is installed in a rack of other test equipment that runs all the time the switch should be on the back so it can't be accidentally turned off from the front of the TM503.

Apparently the latter solution (switch on the back) won the argument at Tek this time around.

Dennis Tillman W7PF
PS: I always thought Tek came up with a clever solution with the way they brought the power switch out to the front of the TM503 and took up virtually no space to do it.

-----Original Message-----
From: Chuck Harris
Sent: Tuesday, April 09, 2019 1:49 PM
Subject: Re: [TekScopes] Unusual TM5xx(x) MF - its not a TM500 or a
TM5000

I do have a TM503A, and it is pretty close to the
TM503 in design, only simpler.

Switch is on the back panel,
IEC power connector,
No side handle,
Round spool type feet on the back for winding the cord.
No 50 pin D style connector on the back

My 503A spends all of its time on a shelf, not being used in
preference for the front power switch 503's.

-Chuck Harris

Dennis Tillman W7PF wrote:
Hi Bob,
It would be very misleading if these unusual hybrids were referred
to as TM502A, TM503A, etc.
There is a TM502A (I have two) and it is nothing but an updated
version of a TM502. It is clearly marked at the front as a TM502A.
There are no special wirings of either slot that would prevent any
TM500 plugin from working properly. There is no additional barrier
that would prevent any TM500 plugin from being used in either slot.
I don't have a TM503A (if one exists) so I can't say how that
differs from a TM503 but it would have to have three fully functional
slots and no additional barriers or a rewired pass transistor
dedicated as a regulated power supply for the middle slot.
This unusual three wide mainframe I am describing has NO MARKINGS on
it to indicate what it is. Apparently Tek avoided the question
entirely of what exactly it is by not saying anything at all. I do
have an AM503 that came from an AM503S stand-alone instrument that I
described in my previous email. It is just an ordinary AM503 but it
has THREE labels on it. The first label, which is in the usual place,
is the original serial number it was given: B086364. The next label
says IDENTIFICATION and it lists this plugin as AM503S. The last label
is another serial number (presumably for the entire stand-alone AM
503S instrument package and it is: B013019.
Dennis Tillman W7PF


--
Dennis Tillman W7PF
TekScopes Moderator

 

I just uploaded a paper I wrote explaining how to modify one of these unusual 3 wide TM mainframes into an ordinary TM503. It requires no parts and it takes about an hour to do. It is easy.

The paler is at:
https://groups.io/g/TekScopes/files/Modification%20of%20an%20Unusual%20Three%20Wide%20TM%20Mainframe%20into%20an%20ordinary%20TM503

Dennis Tillman W7PF



--
Dennis Tillman W7PF
TekScopes Moderator