5000 series power supply potentiometers


Dave Peterson
 

I have a 5103N in which the 30v adjust, R858, a 100 ohm 1/4w potentiometer, PN 311-1120-00 has failed. It's innards have rotted and fallen out. The resistance goes infinite as soon as it is turned from its limit. Results in the 30v output jumping from ~26v to 40v with no variability.

I've done some preliminary searching without finding any good info. Sphere does seem to have any. I get the feeling these are a fairly common part - I see them in my 5111A and 5440 scopes as well as some plug-ins. Of course the values will be different in those applications.

Are these pots generally available? Who is (are) the manufacturer(s)? How are these pots referred to in the Tek Scopes community?

Thanks,
Dave


Ed Breya
 

You can use almost any pot that has the same R, and fits in the spot. Nothing special.

Ed


 

Dave,

I see the exact part (Tek P# 311-1120-00, CTS P# 201-YA5531) on eBay for eight bucks (plus $3.68 shipping) which seems a bit steep, but you get two pieces for that price (still a bit steep, maybe). Here is the item (https://www.ebay.com/itm/193605708230) and they do have the "Make an Offer" button enabled, so maybe?

The part seems to have a 4 pin footprint. Obviously two of those pins must be common (probably the wiper), so you should be able to fit one of those blue Bourns cermet trim pots in the same place by bending one pin to meet one of the common pads for the old pot. Those can be had ten for $8.24 on eBay (free shipping, from China! https://www.ebay.com/itm/313619649115), or you could just buy them from a reputable source.

Also, while perusing the 5103 service manual I found the list of options: it looks like you have Option 78: P11 Phosphor, which is "best suited for waveform photography."

-- Jeff Dutky


Dave Peterson
 

What the heck! I looked there!

Well you have the touch Jeff. eBay likes you better?

I'm curious why the scope has the serial number and option windows on the back plate, and the option window isn't marked. Perhaps someone put the P11 tube in later? Might explain the bit of glass found in the scope. Though it looks more like a shard of plate glass. For whatever that's worth. The blue is lovely.


Thanks again.

Dave

On Wednesday, July 28, 2021, 11:26:14 PM PDT, Jeff Dutky <jeff.dutky@gmail.com> wrote:

Dave,

I see the exact part (Tek P# 311-1120-00, CTS P# 201-YA5531) on eBay for eight bucks (plus $3.68 shipping) which seems a bit steep, but you get two pieces for that price (still a bit steep, maybe). Here is the item (https://www.ebay.com/itm/193605708230) and they do have the "Make an Offer" button enabled, so maybe?

The part seems to have a 4 pin footprint. Obviously two of those pins must be common (probably the wiper), so you should be able to fit one of those blue Bourns cermet trim pots in the same place by bending one pin to meet one of the common pads for the old pot. Those can be had ten for $8.24 on eBay (free shipping, from China! https://www.ebay.com/itm/313619649115), or you could just buy them from a reputable source.

Also, while perusing the 5103 service manual I found the list of options: it looks like you have Option 78: P11 Phosphor, which is "best suited for waveform photography."

-- Jeff Dutky


 

Aren't the CRTs in the 5000-series ceramic neck with a plate glass face? The CRT may well have been replaced after something unfortunate happened to the original one.

I'm really jealous about the blue phosphor screen, that or the green/orange phosphor is something that's on my collection list. I'm still kicking myself that I missed out on a 485 with a P11 phosphor CRT. That would have checked two boxes at once, and it would have been a joy forever.

-- Jeff Dutky


Dave Peterson
 

Looks like my tired brain typed in a cross of two part numbers - crossed rows in the E Parts List. Not as bad as crossing streams, but yeah, there ya go. SUE - stupid user error.

I have some 10k pots that go down to 30 ohms that are of somewhat similar construction. I'm going to try soldering/hacking one in while I wait for the eBay seller to contemplate my low-ball offer for two of the 311-1120-00's. I can/could/will head down to San Mateo Electronics to see what they have. I need to get some teflon wire to repair some overheated ones between the Z-axis board and the CRT. I think I saw an interesting Y-tube video of someone examining the beads-on-a-string pattern wire makes when heated to failure in a vacuum. Looks like that, only more like braided string. Weird, but fun.

Back on topic - my query really was, how are these pots colloquially referred to? Composition pots? Something else? What can I search for online that's similar, if not the same, in the modern supply chain? I'll pay this eBay guy for instant gratification purposes, but I prefer to find like-kind replacements over hacking something in. It's like trying to match Tek-blue paint. I don't have to, but would like to keep to original as much as possible. These seem so ubiquitous in the 5000/TM500 realm that I'm surprised I'm not finding them on Sphere, etc.


Dave Seiter
 

Wow, I've never heard of San Mateo Electronics before, and it's less than 20 miles away!  How did that happen?!
-Dave

On Thursday, July 29, 2021, 10:57:10 AM PDT, Dave Peterson via groups.io <davidpinsf=yahoo.com@groups.io> wrote:

Looks like my tired brain typed in a cross of two part numbers - crossed rows in the E Parts List. Not as bad as crossing streams, but yeah, there ya go. SUE - stupid user error.

I have some 10k pots that go down to 30 ohms that are of somewhat similar construction. I'm going to try soldering/hacking one in while I wait for the eBay seller to contemplate my low-ball offer for two of the 311-1120-00's. I can/could/will head down to San Mateo Electronics to see what they have. I need to get some teflon wire to repair some overheated ones between the Z-axis board and the CRT. I think I saw an interesting Y-tube video of someone examining the beads-on-a-string pattern wire makes when heated to failure in a vacuum. Looks like that, only more like braided string. Weird, but fun.

Back on topic - my query really was, how are these pots colloquially referred to? Composition pots? Something else? What can I search for online that's similar, if not the same, in the modern supply chain? I'll pay this eBay guy for instant gratification purposes, but I prefer to find like-kind replacements over hacking something in. It's like trying to match Tek-blue paint. I don't have to, but would like to keep to original as much as possible. These seem so ubiquitous in the 5000/TM500 realm that I'm surprised I'm not finding them on Sphere, etc.


Dave Peterson
 

I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.


Harvey White
 

Trimpots.

Harvey

On 7/29/2021 1:57 PM, Dave Peterson via groups.io wrote:
Looks like my tired brain typed in a cross of two part numbers - crossed rows in the E Parts List. Not as bad as crossing streams, but yeah, there ya go. SUE - stupid user error.

I have some 10k pots that go down to 30 ohms that are of somewhat similar construction. I'm going to try soldering/hacking one in while I wait for the eBay seller to contemplate my low-ball offer for two trof the 311-1120-00's. I can/could/will head down to San Mateo Electronics to see what they have. I need to get some teflon wire to repair some overheated ones between the Z-axis board and the CRT. I think I saw an interesting Y-tube video of someone examining the beads-on-a-string pattern wire makes when heated to failure in a vacuum. Looks like that, only more like braided string. Weird, but fun.

Back on topic - my query really was, how are these pots colloquially referred to? Composition pots? Something else? What can I search for online that's similar, if not the same, in the modern supply chain? I'll pay this eBay guy for instant gratification purposes, but I prefer to find like-kind replacements over hacking something in. It's like trying to match Tek-blue paint. I don't have to, but would like to keep to original as much as possible. These seem so ubiquitous in the 5000/TM500 realm that I'm surprised I'm not finding them on Sphere, etc.





Renée
 

wow...time to make a visit....I am near Napa but....with loss of Halted, Haltek, Weird Stuff, etc.....definitely on my stop list when below the bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.




Ozan
 

I highly recommend Anchor Electronics https://anchor-electronics.com for new components and Excess Solutions http://www.excesssolutions.com for Halted like experience (they bought HSC inventory) if you are in South Bay Area.

Ozan

On Thu, Jul 29, 2021 at 12:06 PM, Renée wrote:


wow...time to make a visit....I am near Napa but....with loss of Halted,
Haltek, Weird Stuff, etc.....definitely on my stop list when below the
bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I
looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right,
1.1M resistors in small quantities. Google maps found them for me:
https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like
going back in time. A good old fashioned shop. Go there! Spend lots of money!
Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.





Dave Peterson
 

Thanks for the references Ozan.

I've been studying Mouser's catalog. Looks like Amphenol makes a fair equivalent:
https://www.mouser.com/ProductDetail/Amphenol-Piher/PT15LV18-101A2020?qs=sGAEpiMZZMtC25l1F4XBU%252Bo9fLf9DWN0PIofWswK870%3D

I hesitate to order from Mouser with the $8 shipping (for a couple/few $0.80 parts), but given what the #### on eBay is expecting to get for actual 311-1120's I'd just as soon order from Mouser.

Or a local dealer. I work in the South Bay (going back to the office for my first real RTO visit Monday), so a side trip to Anchor or Excess might well be worth it. Need to research their catalogs/inventory first.


Dave

On Thursday, July 29, 2021, 12:54:59 PM PDT, Ozan <ozan_g@erdogan.us> wrote:

I highly recommend Anchor Electronics https://anchor-electronics.com for new components and Excess Solutions http://www.excesssolutions.com for Halted like experience (they bought HSC inventory) if you are in South Bay Area.

Ozan


On Thu, Jul 29, 2021 at 12:06 PM, Renée wrote:


wow...time to make a visit....I am near Napa but....with loss of Halted,
Haltek, Weird Stuff, etc.....definitely on my stop list when below the
bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I
looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right,
1.1M resistors in small quantities. Google maps found them for me:
https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like
going back in time. A good old fashioned shop. Go there! Spend lots of money!
Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.





Dave Seiter
 

Halted had a north bay location, did it go belly-up too?
-Dave

On Thursday, July 29, 2021, 12:06:28 PM PDT, Renée <k6fsb.1@gmail.com> wrote:

wow...time to make a visit....I am near Napa but....with loss of Halted,
Haltek, Weird Stuff, etc.....definitely on my stop list when below the
bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.





Tom Lee
 

Sadly, the Rohnert Park HSC store closed first, back in mid-2013.

-- Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 7/29/2021 14:01, Dave Seiter wrote:
Halted had a north bay location, did it go belly-up too?
-Dave
On Thursday, July 29, 2021, 12:06:28 PM PDT, Renée <k6fsb.1@gmail.com> wrote:
wow...time to make a visit....I am near Napa but....with loss of Halted,
Haltek, Weird Stuff, etc.....definitely on my stop list when below the
bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.












Tom Lee
 

Oh, and they also once had a Sacramento store. That one closed years before the Rohnert Park one.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 7/29/2021 14:01, Dave Seiter wrote:
Halted had a north bay location, did it go belly-up too?
-Dave
On Thursday, July 29, 2021, 12:06:28 PM PDT, Renée <k6fsb.1@gmail.com> wrote:
wow...time to make a visit....I am near Napa but....with loss of Halted,
Haltek, Weird Stuff, etc.....definitely on my stop list when below the
bay bridge!
Thanks
Renée

On 7/29/21 11:32 AM, Dave Peterson via groups.io wrote:
I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.