• Please review our updated Terms and Rules here

11/44 psu diodes

H

harry

Experienced Member
Joined
Oct 19, 2007
Messages
310
Location
United Kingdom
I had to remove the psu on my 11/44 as there was no 'dc ok' light showing when switched on, I have stripped the psu and found one of the large diodes have failed. This is a Unitrode item marked as "USD 5111F " I am trying to locate some replacements , (I was going to replace all four while it is apart) I am not having much luck finding a spec sheet or data for this diode, Farnell, RS, and such have no reference. Can anyone possibly help to identify the spec .Perhaps an old Unitrode catalogue or such? so I can source the correct equivalent diodes. It has 1/4 unf stud mount, with aprox 4 Inch rubber sheathed tail and 3/16 hole in the end lug.
thanks
Harry
 
My 11/750, which is using PSUs (H7104C/D) with a very similar design, also had failed rectifier diodes. In my case they were marked USD5096F.

When looking into the printset of the 11/44 a couple of years ago when I refurbished my 11/44 I noted that the diodes most likely are the same. But I don't know for sure.

I bought these for my 11/750 but they seems to be available on Ebay as well.

The strange thing is that it is advertised as a 35A diode which cannot be true. It just to has to be able to handle more since the output of the 11/750 supply is 135A at 5V. The 11/44 printset (H7140 PSU) list it as "RECTIFIER PLU=45 I=60" while the 11/750 (H7104C/D) print sets says "60 AMP POWER SCHOTTKY DIODE"

Actually 60 A seems to be more reasonable to me.

Like you I never found any data sheet from Unitrode on this one and my guess it was some kind of special selection for DEC. I searched old data books as well and nothing turned up.
 
Mattislind,
Thanks for reply, I did see the I=60 on the parts list for the H7140 psu, and so had been looking for some 60 amp diodes with stud and tail, thanks for the links to the USD5096f
if these have worked for you, then I may just order some and get things back together. did you bond the yellow rings back on to the diode body when you installed them ?

Harry
 
Kenwickvs

Thanks for pointing to the MBR6035. looks to be the correct spec, just would need the heavy wire tails with lugs fitted , otherwise should be ok.

Harry
 
harry said:
Mattislind,
Thanks for reply, I did see the I=60 on the parts list for the H7140 psu, and so had been looking for some 60 amp diodes with stud and tail, thanks for the links to the USD5096f
if these have worked for you, then I may just order some and get things back together. did you bond the yellow rings back on to the diode body when you installed them ?

Harry
Click to expand...

It was working fine. I ran it for several hours with the FPA installed (it consumes plenty of power).

I don't recall anything about a yellow ring that has to be bonded onto the body of the diode.

I did check out other schottky rectifiers and bought a few that I found cheaply just in case. They didn't have the tail. But in that case I would replace all four (three in the H7104C 2.5V supply). Don't remember what part I got though, and I can't check right know since I am on vacation.
 
You must log in or register to reply here.
Back
Top