Aeroflex IFR2025 without AC/DC power supply - Fixed

[Miti]

I've got this lovely IFR2025 RF signal generator without the AC/DC power supply. Looking through the service manual... yes, there's a free, detailed, old school service manual online,  I saw that it needs +5V, +12V, +24V and -12V so I dug into my power supplies box and connected four, brick type power supplies with the correct or better current capability.
The result is in the pictures. The internal supply voltages are OK, the output seems to be pretty much spot on, or at least I can't see any issue with my spectrum analyzer and frequency counter.
I was afraid that it may need a special power up sequence but it doesn't seem to care.
I intend to use some separate Mean Well ?? enclosed power supplies RS-15, RS-25, LRS-35 series. I know Delta, Lambda, CUI, etc., but this Mean Well is new to me.
Do you have any experience with them? They are very cheap, under 20CAD per supply.
If I can repair this instrument, it would be a really nice addition to my lab.
For those who know it, what should I look for, some subtle issues that it may have?
Thanks,
Miti

[Miti]

More pictures.

[George Edmonds]

Hi

The original switch mode supply was made by Powertron in the UK.

You should find a Meanwell single supply, the +24VDC may be the only difficult supply, but I have memories of a Meanwell supply that I used in a HP spectrum analyzer that did have the +24VDC supply along with the other voltages that you need.

Meanwell are a well established manufacturer of good  quality switch mode power supplies.

The only stock problems with a 2025 that I know of are the HyQ 10MHz frequency standard and the LCD display.

George G6HIG

 

[George Edmonds]

Hi

Sorry the service manual that I have for a IFR2025 is in error.

The 202x used Alpha or Omega (Lambda) power supplies, not Powertron.

George G6HIG
 

[Miti]

Thanks George!

The LCD looks fine on mine but what’s the problem with the HyQ 10MHz TCXO?
I was thinking of looking for an NDK OCXO to replace it but then , I have a GPSDO with lots of outputs, so I could feed external reference if I need accuracy.
I looked after a multi output power supply but no one I could find meet all the current requirements. I will go with four modules. I have an open frame Delta 12V, 4A, I need three more and I will go with Mean Well.
The good part about 4 separate power supplies, I can adjust them all to the exact voltage.

[George Edmonds]

Hi

The HYQ tends to fail and produces an incorrect frequency, it is also the low spec 10MHz standard used in the Marconi/IFR signal generator range.

The NDK is a higher spec unit, the NDK part number used by Marconi/IFR is part number END3032A.  The PCB track work accommodates this without an change.  The END3032A can sometimes be found on evilbay as it was used in a number of Marconi/IFR products.

George G6HIG 

[Miti]

It needs 5V-2.8A, 12V-2.3A, -12V-0.6A, 24V-0.6A. Do you have a picture or a model number of the power supply? What about the OCXO, do you sell that as well?

[TheMG]

What happened to the original power supply? Did it fail and the previous owner discarded or misplaced it?

That's kind of a shame, because the original power supply is good quality and is very easily repairable. I have a 2025 I picked up on eBay for cheap because it didn't power up, was able to easily and quickly get the power supply working again with a <1 cent part.

[Miti]

What happened to the original power supply? Did it fail and the previous owner discarded or misplaced it?

That's kind of a shame, because the original power supply is good quality and is very easily repairable. I have a 2025 I picked up on eBay for cheap because it didn't power up, was able to easily and quickly get the power supply working again with a <1 cent part.

It was installed in a 2025 with more options but a bad PS. I don't know what happened with the bad one.

PS: The good part about installing 4 power supplies is that they are all regulated, unlike the multi output one that can control only one output, from what I've seen in the case of +5, +12, +24, -12, it is the 5V that is in the control loop.The others are at the mercy of the load. Not sure how important this is though and how variable the load is with the frequency and output level, modulation, etc. The concern is the inrush current may blow the original 2A fuse.
Of course I would like to install the original model which I expect to be carefully selected or properly designed for this application, but from what I see, chances are slim.

[Miti]

I'll find the PSU tomrrow and take some pictures if the voltages/current ratings are the same or better.

This is what the original one looks like. I found it in another post on Eevblog. The manual says the model is COUTANT LAMBDA HVI-60-47A.

[Kosmic]

For reference, this is the power supply of my IFR2025.

[Kosmic]

I've got this lovely IFR2025 RF signal generator without the AC/DC power supply. Looking through the service manual... yes, there's a free, detailed, old school service manual online,  I saw that it needs +5V, +12V, +24V and -12V so I dug into my power supplies box and connected four, brick type power supplies with the correct or better current capability.
……….

Could you do me a favor and take a close shot where the front panel bnc are connected on the main board ? On my unit they are on the back panel only and I want to move them in the front.

[Miti]

Could you do me a favor and take a close shot where the front panel bnc are connected on the main board ? On my unit they are on the back panel only and I want to move them in the front.

Thanks for the pictures! Does this PS have PF correction or what's T1 for and why does it have so many filter caps?

Here is the close up shot. EXT MOD INPUT goes to PLL and LF OUTPUT goes to PLK. If you look in the service manual, fig. 7-65, the connectors are symmetrical, pins 1&3 GND, pin 2 signal.

Edit: Lol, T1 is too small for PFC.

[fcb]

Ive got a Marconi 2023 (same series as your 2025 I think).  I can pop the lid off if you need another point of reference, measurements etc..

[George Edmonds]

Hi

The two coax connections are not original.  Marconi would never have soldered them on, they would have used plugs.

George G6HIG

[Miti]

Ive got a Marconi 2023 (same series as your 2025 I think).  I can pop the lid off if you need another point of reference, measurements etc..

Thanks fcb but at this point I have all I need. Most likely I won't find the right power supply so I'll order separate modules today to install them in the weekend. Do you see anything wrong with 4 separate modules? I can only think of the inrush current that may blow the 2A fuse. If so, I'll install a 3 or 3.5A.

[George Edmonds]

Hi

Hang on until next week, am looking at a IFR2935 for a PSU  hopefully this weekend.

George G6HIG

[Miti]

Hi

The two coax connections are not original.  Marconi would never have soldered them on, they would have used plugs.

George G6HIG

I think you're right. Both BNC connectors and the N connector look funny. I have couple more generators at work (sealed with cal. stickers  ) and none of the connectors have nuts on the outside. They must be inside. My generator have outside nuts on all three connectors, I wonder why? The BNC I understand, maybe it didn't have front connectors but the N connector? It doesn't have rear output. 
Also, if you look at the rigid cable from the output connector to the output of the RF tray, it is too long, so somebody bent it.

[Miti]

Hi

Hang on until next week, am looking at a IFR2935 for a PSU  hopefully this weekend.

George G6HIG

Thanks George, in this case I will wait.

Cheers,
Miti

Edit: I'm also interested in the OCXO, if you don't need it...

[Kosmic]

Hi

The two coax connections are not original.  Marconi would never have soldered them on, they would have used plugs.

George G6HIG

I think you're right. Both BNC connectors and the N connector look funny. I have couple more generators at work (sealed with cal. stickers  ) and none of the connectors have nuts on the outside. They must be inside. My generator have outside nuts on all three connectors, I wonder why? The BNC I understand, maybe it didn't have front connectors but the N connector? It doesn't have rear output. 
Also, if you look at the rigid cable from the output connector to the output of the RF tray, it is too long, so somebody bent it.

Probably originally had connectors on the back like mine­. Binding the original rigid cable is not necessarily a bad idea. Calibration would stay the same.

[Miti]

So does your generator have an RF output at the back of the RF tray, or the rigid cable goes all the way from the front to the back?

Edit: I get it now. Option 5 has rear panel connectors. Mine was modified to bring the output to the front panel and to add the two BNCs, so the rigid cable that was going all the way to the back, was bent as needed. That may or may not affect the impedance.

[Kosmic]

Yes, I also got option 5 (back connectors).

[fcb]

Ive got a Marconi 2023 (same series as your 2025 I think).  I can pop the lid off if you need another point of reference, measurements etc..

Thanks fcb but at this point I have all I need. Most likely I won't find the right power supply so I'll order separate modules today to install them in the weekend. Do you see anything wrong with 4 separate modules? I can only think of the inrush current that may blow the 2A fuse. If so, I'll install a 3 or 3.5A.

No worries.  I have the front connector version BTW.

[Miti]

Hi George,

I’m curious about that power supply... and maybe OCXO?
Did you have time to look for it?

Thanks,
Miti

[George Edmonds]

Hi Miti

Yes I did check the power supply and it is not the same.  see attached photographs.

Best wishes

George G6HIG

[Miti]

It is repaired!

I installed a power supply MeanWell RQ-85D with 4 outputs. I'll have to say that i'm impress with the quality and attention to details of this power supply, I will do a mine tear down in another post. The voltages are spot on, 5.09V, 12.1V, 23.97V, -12.05V so I didn't even need to adjust it.

Happy!