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Re: 2712 issue

 

Hello Howard and all,

As Jon mentioned it can very well be that the mixer diodes have been destroyed.

Below are some level problems I encountered in some of these analyzers.

Please check Q350 - 2N3904 (SMD-marking 1A) in the VR Module. I had a broken one. This transistor gets too hot under normal circumstances because of the combination of UCE en IC. The UCE is about 11,5V and the IC is between 20 and 25mA, in my case 23mA. The dissipation then is between 250 - 300mW and that is a bit too high for a SOT-23. In my case I put in a new one and I cooled it via a heat pad and a small 1¡±x 1¡± aluminum heat-sink of the right (I forgot) thickness against the inside of the lid of the VR Module.

Another thing can be a too low level LO signal coming from J380 from the 1st LO Buffer Amp. The level should be about +13dBm, but in one of my analyzers this was way lower. Please measure that if you can. The problem in my case turned out to be caused by two leaking SMD electrolytic capacitors inside this hard to reach unit. Residue from the leaking (a bit of black sticky fluid) was hiding under a SMD capacitor C292. Under this resistor there was a high impedance track going to the input of the opamp that stabilizes the LO output level a bit to a certain level. In the end I removed all the following components that I had my doubts on in that unit: SMD components C292, C298, C828, R280, R166, R168, R266, C267, C160 and R264. I cleaned everything and put them back. The problematic SMD electrolytics C180 10¦ÌF/50V and C392 10¦ÌF/50V were replaced by new ones of course.

Good luck and please keep us updated.

Jaap
5B44 Dual Timebase parts - knobs wanted!

 

Hi all,
I have a rather sad 5B44 with broken timebase knobs. My copy of the service manual is a not a clear enough scan to tell for sure which part numbers these are so I cannot give specific references.
The knob(s) are concentric and have skirts with the sec/div marked on them - or would have if it still had them.
Can anyone help with identifying the correct part numbers please?
Does anyone have a non functioning 5B44 with intact knobs they would sell for parts or part out themselves please?
Or does anyone know where to look for these parts?
I have been looking on fleaBay intermittently but not much luck esp. with not knowing the exact part numbers I need.
Thanks and kind regards,
Daniel
Re: Is this the BSM Connector?

 

Just went to track it down. That's the one!



Thanks for the lead. I suppose they're not as rare as eBay made me think.
Re: Is this the BSM Connector?

 

Fair Radio Sales is another source (at least until the end of June, 2024) for these connectors.

Shaun M.
Is this the BSM Connector?

 

I've been trying to find a BSM panel jack connector for a while now. Usually, it's the 012-0127-00 that the manual calls out. I had nearly given up. But I was visiting a friend of mine who owns a Collins R390A and he was showing me the features. I noticed the IF connector in the back looks just like the BSM connectors on the 7T11A, 7D14, Sampling heads, etc. When I started to search for this connector, it was much easier to find. Now I'm not a HAM myself, but he certainly is and I know what they are many here. So it's possible this is old news. But anyone looking:
Re: Having a lot of problems with this "upgraded" groups.io user interface

 

I keep some old machines running for special purposes. I still have a working Win98 laptop with an original Pentium for old programs that have to read from and write to the UART registers. I need them to program some vintage broadcast equipment which was developed in the Windows 3.1 days. I have a 32 bit WinXP laptop for programs that are unhappy under 64 bit versions of Windows.

Nowadays my daily drivers are Win10 Pro 64 bit machines.
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
Re: Having a lot of problems with this "upgraded" groups.io user interface

 

Tom,

Basically the costs are relevant if the present software can no longer be upgraded to add new features if the older machine won¡¯t fully support migration to a new OS (i.e drivers will no longer work, etc.). Then if that is the case you must move on to a new OS on a new machine to accomplish that task leaving the older machine behind and reinstalling upgraded software from the same manufacturers (if they still exist). Get my ¡°can of worms¡± theory here?

Things are working fine here. I have plenty of resources to accomplish my tasks. The main thrust is to keep dancing around newer software/products so as to minimize time and money wasted (having to do ¡°science experiments¡±) and get on with life. My actual goal is to serve clients who have those legacy systems. It sometimes becomes difficult to deal with older systems that have incurred failures whereby they either lose control of high $$ value systems or cannot interface to them in other ways.

Before this topic grew legs I believe the original interest was why many people are experiencing various anomalies regarding use of the groups.io system after an apparent ¡°upgrade¡± causing more wasted time trying to find approaches around the problems encountered. I have found a simple solution since then without spending a large effort. Groups.io is merely a convenience, not a requirement.

Greg
Re: Having a lot of problems with this "upgraded" groups.io user interface

 

On Mon, 13 May 2024 at 18:11, Greg Muir via groups.io <big_sky_explorer=
[email protected]> wrote:

A couple of closing comments from here¡­..

Tom Gardner:
With respect to your comment: ¡°Why would buying a new computer mean you
must throw out the existing one? Can't you run old stuff on the existing
computer, and new stuff on the new computer? ¡°
I believe that there has been no mention of disposing of older functional
computers in this topic.
Probably not, but you did previously write...
On Sun, 12 May 2024 at 18:00, Greg Muir via groups.io <big_sky_explorer=
[email protected]> wrote:

...
But this doesn¡¯t address the elephant in the room¡­ having to either
upgrade (sometimes purchase) legacy software or purchase new at a cost.
That is the big chunk of money.

Those costs are only relevant if you are disposing of the existing machine.

Anyway, multiple people have indicated multiple ways forward for you. So...
over to you.
Re: Zero cost electrolytic can adapter

 

One detail I want to add. If the diameter of the replacement condensers don't fill the can to the limit, I like to use a strip of plastic cut from a frozen food microwave tray to form a ring inside the can to give some strength when the top of the can is put back on.

?? Bruce Gentry, KA2IVY

On 5/13/24 13:28, n4buq wrote:
Just to clarify, the can is turned upside-down for that.

Barry - N4BUQ

I've done this by making the cut about 1/2" from the top of the can. A hacksaw
blade taped to a small piece of wood allows one to cut and slowly spin the can
while sawing so that the cut is all the way around. It makes for a pretty
square cut. I think I used heat-shrink the last time I did that as well.

Barry - N4BUQ

I have done this on a lot of multi-cap cans in old monitors.

The multi cans bulge at the bottom, so I cant use a pipe cutter reliably.
Have to use a hacksaw...with very fine teeth.

Clean up with a half-round file and then fine sand paper glued to a glass pane
(for flatness).

To reassemble the cans, I have used aluminum tape in the past.
But I'm going to try clear heat shrink tubing on the next one I do.
I think that might look nicer.
Re: Zero cost electrolytic can adapter

 

Just to clarify, the can is turned upside-down for that.

Barry - N4BUQ

I've done this by making the cut about 1/2" from the top of the can. A hacksaw
blade taped to a small piece of wood allows one to cut and slowly spin the can
while sawing so that the cut is all the way around. It makes for a pretty
square cut. I think I used heat-shrink the last time I did that as well.

Barry - N4BUQ

I have done this on a lot of multi-cap cans in old monitors.

The multi cans bulge at the bottom, so I cant use a pipe cutter reliably.
Have to use a hacksaw...with very fine teeth.

Clean up with a half-round file and then fine sand paper glued to a glass pane
(for flatness).

To reassemble the cans, I have used aluminum tape in the past.
But I'm going to try clear heat shrink tubing on the next one I do.
I think that might look nicer.
Re: Zero cost electrolytic can adapter

 

I've done this by making the cut about 1/2" from the top of the can. A hacksaw blade taped to a small piece of wood allows one to cut and slowly spin the can while sawing so that the cut is all the way around. It makes for a pretty square cut. I think I used heat-shrink the last time I did that as well.

Barry - N4BUQ

I have done this on a lot of multi-cap cans in old monitors.

The multi cans bulge at the bottom, so I cant use a pipe cutter reliably.
Have to use a hacksaw...with very fine teeth.

Clean up with a half-round file and then fine sand paper glued to a glass pane
(for flatness).

To reassemble the cans, I have used aluminum tape in the past.
But I'm going to try clear heat shrink tubing on the next one I do.
I think that might look nicer.
Re: Having a lot of problems with this "upgraded" groups.io user interface

 

A couple of closing comments from here¡­..

Tom Gardner:
With respect to your comment: ¡°Why would buying a new computer mean you must throw out the existing one? Can't you run old stuff on the existing computer, and new stuff on the new computer? ¡°
I believe that there has been no mention of disposing of older functional computers in this topic.

Other:
Aside from my previous mention of having an old laptop running WIN3.1 plus DOS, there is also a (original) IBM 5160 PC/XT with 5-1/4 floppy & 10 meg HD running DOS 2.0 on the shelf ¡°just in case¡±. There still may be an original 5150 (8088 based) floating around here somewhere. I vaguely remember paying around $1500 for that box. I do know that there is also an AT in a box in storage containing that ¡°screaming¡± 286 processor (the 6 MHz processor speed was known to give users nosebleeds).

While working for a company that produced embedded software we gained a contract with MicroSquish to bundle our program in their soon-to-be-released new OS version to add additional features to other manufacturers add-on hardware. This required occasional visits to Redmond to interface with their programmers to exchange information and review the development cycle of both their and ours software.
While at one meeting I found MS talking with Intel engineers. Listening to their conversation I quickly realized that they were basically in bed with each other in regards to product development that favored each other¡¯s products. It was sort of a:
Intel: ¡°What do you need to make your OS function uniquely?¡±
MS: ¡°Well, we need (this and that)¡±
Intel: ¡°We will design a new processor to handle (this and that)¡±

There was one instance where Intel decided to design an entire dial-up modem chipset to accommodate some special communication features that also embodied use of our software. We received a prototype board from Intel for acceptance testing. To say the least I was quickly struck by the fact that Intel should have stuck to their original business of making only processor ICs. The board was nearly one foot square populated with several dozen proprietary devices that probably would have sold if put into production for a thousand $$ - all for a simple dial-up modem. It never made it out of the chute. Later all of the big modem manufacturers released their own products containing a single chipset solution.

In respect to today¡¯s new PC/OS offerings the multimedia (gaming, etc.) and other home oriented user applications have seemed to override the original technical application functionality of many products for us gearheads. In addition the newer OS versions have also buried considerable access to the ¡°nuts and bolts¡± one can use to deal with anomalies when troubleshooting both hardware and software issues. That is why I still like dealing with the older NT versions where you could get inside of a system with ease. (This is coming from a person who originally grew his teeth on DOS.)

Greg
Re: Zero cost electrolytic can adapter

 

When I rebuild a condenser, I use blue shrink wrap over it because it covers the cut seam and is authentic, I have seen plenty condensers from the factory with blue sleeves. I put a wrap of aluminum foil around the seam so the top part of the can is grounded to the bottom part.

?? Bruce Gentry, KA2IVY

On 5/13/24 11:54, Chris Wilkson via groups.io wrote:
I have done this on a lot of multi-cap cans in old monitors.

The multi cans bulge at the bottom, so I cant use a pipe cutter reliably.
Have to use a hacksaw...with very fine teeth.

Clean up with a half-round file and then fine sand paper glued to a glass pane (for flatness).

To reassemble the cans, I have used aluminum tape in the past.
But I'm going to try clear heat shrink tubing on the next one I do.
I think that might look nicer.
Re: SC504

 

You can try making one yourself. As far as I know, it's just blue clear plastic. Someone else here made some tek CRT shields using some blue plastic.

I'm not sure what to do with the tan though. Maybe glue another peice of blue plastic? I can get you dimensions and measurements as have an SC502.

Benjamin
Re: Zero cost electrolytic can adapter

 

I have done this on a lot of multi-cap cans in old monitors.

The multi cans bulge at the bottom, so I cant use a pipe cutter reliably.
Have to use a hacksaw...with very fine teeth.

Clean up with a half-round file and then fine sand paper glued to a glass pane (for flatness).

To reassemble the cans, I have used aluminum tape in the past.
But I'm going to try clear heat shrink tubing on the next one I do.
I think that might look nicer.
Re: Looking for leaded electrolytic capacitors

 

My request for "new" is because I'd rather buy from a reputable source. I could probably still find some on other online sources but with all the "fake" items being reported, I'm just more comfortable with places like Mouser, Digikey, etc.

Thanks,
Barry - N4BUQ

"is NOS ok or brand spanking new"

Great question!

There are good reasons why a cap is spec'd for 85¡ãC or 105¡ãC, or 1000hrs or
5000hrs, or a shelf life of 10,000hrs or 100,000hrs.
It goes well beyond the electrolyte formula.
There's also the quality of the rubber seals, and the actual foil composition.

Simply put, a low-spec NOS 85¡ãC cap is one you don't want to install after about
3-5 years on the shelf.
Whereas a high-spec NOS 105¡ãC or 125¡ãC is generally good for about 10+ years on
the shelf.

Regarding brand-new - if it's a well-established series, then certainly
preferable.
But if it's a recently introduced series, I normally wait about 2-3 years before
using them.

I remember that I had serious problems with Panasonic FM's failing in the early
years.
That really surprised me, being a lifelong fan of Matsushita/Panasonic.
No bulging, just capacitance decreasing and high ESR.
No, they weren't fakes.
I had a lot of comebacks, so I stopped using them for a couple of years.
Later, I returned to using them with no problems.

And Chemicon also had similar problems with a high-spec 105¡ãC KYx or KZx series
- I don't remember which.

So, crap happens even at the best people, and problems need time to be ironed
out.


Beyond that, on PSU power rails, you GENERALLY do NOT have to replace an old cap
with the same numbers.
For example, an old large 47uF can generally be replaced with a small 100uF or
220uF with no issues.
(Perhaps that's why <100uF caps are becoming scarce now).
The cap's voltage rating can be 2-3 times the actual circuit voltage with no
issues.
Of course, you should check and understand the actual circuit requirements,
before making any decision to change the original ratings.

Menahem Yachad
www.condoraudio.com
Re: Looking for leaded electrolytic capacitors

 

Thank you, Drew. That's very good information and what I was looking for. Those Barker-Microfarad choices sure look good. Too bad they're not selling them through outlets such as Mouser, Digikey, etc. With Nichicon moving away from some of their lines, perhaps those outlets will look to Barker-Microfarad fill the void.

Thanks again,
Barry - N4BUQ

I remember getting the EOL notices a couple years ago. I guess it's finally
here. FWIW, they still have a few thousand in most of those UHE and values at
Mouser. I still have plenty Nichicon in the bins so we'll see how long that
lasts me.

I spend about 20% of the repair characterizing and sorting components before I
start so I understand the predicament. I've been getting manufacturer sample
kits to see if there's anything that impresses me. Here's what I've been
preparing to transition to:

Chemi-Con KYB Series:
- The Good - All around excellent, Low Z, Long life, Lots of sub 100?F values,
High ripple, good prices
- The Bad - Once you get to 100V they become pricey
Chemi-Con PSG: (Organic Polymer Caps)
- The Good - Super low Z, Extremely long life, Similar price range, Excellent
ESR!
- The Bad - Kind of wonky values to what we're used to. Not much below 100?F. No
high voltage.
Chemi-Con KZN:
- The Good - Low Z, Long life, Excellent ESR and high ripple, Many sub 100?F
values
- The Bad - Slightly pricier, Sub 100?F are ¡Ü5000 hours rated,
Panasonic FR & FM Series:
- The Good - Low Z, Excellent prices, all 105¡ãC, lots of sub 100?F options,
Super low ESR
- The Bad - Not much really. I think they're ugly, does that count?
Cornell Dublier KXM & KBM Series:
- The Good - Hits all the marks, low Z, low ESR, good price, lots of sub 100?F
values,
- The Bad - Also ugly, maybe uglier than the Panasonic. Otherwise, a fine cap.
Barker-Microfarad
- The Good - Everything, especially the 510D and made in USA! I thought my
leakage tester was dead when I first sorted them.
- The Bad - Impossible to acquire by hobbyists like myself. A friend who works
in component ordering for Mitsubishi got me a stash. Also, they don't look
cheap. (From the style of them, they must have acquired the licensing from
Sprague or are Sprague or manufacture the Sprague line for Vishay. I'm not
really sure but you'll know what I mean when you see them.)


I'm sure there are many more. I might add I've been shying away from the Ruby's
lately. They used to be another go to brand for me and many others. But during
characterization, they tend to vary a lot more on my bench than the other
brands here. It may be picky, but I don't like unpredictability.

Regards,
Drew
Re: Zero cost electrolytic can adapter

 

I don't put the lid back on.
For me, this only serves to avoid purchasing adapters.
The use of an adapter when repairing a tektronix oscilloscopes enables a good and reliable repair.
It is possible to install modern electrolytes without an adapter,
you just have to pay attention to the fact that the body of the can serves as a jumper
for several points of ground potential. In that case you need to install the wires.
My opinion is that it might be better not to put the can back,
because the electrolyte has better cooling.
I don't know if I'm right with this interpretation, when it comes to the temperature of the electrolyte.
I know that restoring the can is more often used by restorers of old radios,
because in that case the original appearance is still more important.
Re: Looking for leaded electrolytic capacitors

 

"is NOS ok or brand spanking new"

Great question!

There are good reasons why a cap is spec'd for 85¡ãC or 105¡ãC, or 1000hrs or 5000hrs, or a shelf life of 10,000hrs or 100,000hrs.
It goes well beyond the electrolyte formula.
There's also the quality of the rubber seals, and the actual foil composition.

Simply put, a low-spec NOS 85¡ãC cap is one you don't want to install after about 3-5 years on the shelf.
Whereas a high-spec NOS 105¡ãC or 125¡ãC is generally good for about 10+ years on the shelf.

Regarding brand-new - if it's a well-established series, then certainly preferable.
But if it's a recently introduced series, I normally wait about 2-3 years before using them.

I remember that I had serious problems with Panasonic FM's failing in the early years.
That really surprised me, being a lifelong fan of Matsushita/Panasonic.
No bulging, just capacitance decreasing and high ESR.
No, they weren't fakes.
I had a lot of comebacks, so I stopped using them for a couple of years.
Later, I returned to using them with no problems.

And Chemicon also had similar problems with a high-spec 105¡ãC KYx or KZx series - I don't remember which.

So, crap happens even at the best people, and problems need time to be ironed out.


Beyond that, on PSU power rails, you GENERALLY do NOT have to replace an old cap with the same numbers.
For example, an old large 47uF can generally be replaced with a small 100uF or 220uF with no issues.
(Perhaps that's why <100uF caps are becoming scarce now).
The cap's voltage rating can be 2-3 times the actual circuit voltage with no issues.
Of course, you should check and understand the actual circuit requirements, before making any decision to change the original ratings.

Menahem Yachad
www.condoraudio.com
Re: Option 2 not installed on an option 2 DM502A?

 

Well, it looks like I can indeed use a regular PT100 temp probe with this "option 2" instrument. If I put 110 ohms across the LEMO connector, I get a reading of 25 celsius, which aligns with the PT100 chart.
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