AVO VCM MK IV, some diodes

[vahakuja]

Hello,
The Avo VCM MK IV. has on the Plate 6 (Component Board Assembly) four diodes of type 10DE8 (plastic case) and one IR5F4. Unfortunately I did not find any technical data of those types. Could someone kindly advice, which should be suitable replacements for the diodes or inform basic data like voltage and current values. Mentioned type might be old products of IR (International Rectifiers).

Thanks in advanced
Ake
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[Dekatron]

Fast recovery types like BYW96E works very well as replacements for those diodes.

/Martin

[Pamphonica]

Or if you don't have those to hand, you could use 1N5407 or similar at 50p each. You don't need their high ratings, but the large lead diameter makes soldering in to circuit a lot easier as they can be self-supporting, even from one end only.
I am sure the fast recovery diodes are closer in characteristic but you shouldn't notice the difference.
- Jeremy

[vahakuja]

Thank you very of Your guidance.
I’ll look forward that replacements will solve the problem.

Kind regards
Ake

[WME_bill]

Diodes. 10DE8. My data books give for International Rectifier 10D8 = silicon 800V piv, 1A. so yours looks like a different package version. 1N4006 or the 3A 1N5407 suggested by Jeremy "Pamphonica" or any standard diode should be alright. These are all long before Fast Recovery or Soft Recovery types were thought of.
The 1R5F4 appears in my data as a thyristor. 50V,1A, with 0.2ma,0.8V gate. Has your example got a third connection. Very odd, unless it is being used as a diode with the gate permanently switched on. Has anybody come upon this before.? wme_bill

[Dekatron]

In my AVO's the second diode mentione is IRF 2E4 (or I&R 2E4, with the diode symbol in place of the & character), looks like this: http://www.radiomuseum.org/tubes/tube_2e4.html

The 10DE8 diodes is a later version of the earlier 10D8 diode according to an old list I checked at a Swedish surplus seller who had them in stock a long time ago.

The 10D8 was also manufactured by I&R, datasheet for the 10D-series can be found here: http://www.alldatasheet.net/datashee.../IRF/10D2.html, 10D10 picture can be found here: http://www.radiomuseum.org/tubes/tube_10d10.html.

Across the meter you can sometimes find the IRF 1E2 which has a lower rating compared to the IRF 2E4.

Older replacements are SD94 (IRF 2E4) & SD91 (IRF 1E2) which I have found as originally soldered diodes in some AVO Mk IV's.

[Dekatron]

Just spotted an error at the Radiomuseum page on the I&R 2E4, it is not rated at 2A but at 200mA.

I also found a reference for the 5E4 which is rated at 350mA at 400V, so it could actually be a 5E4 in your AVO Mk IV.

/Martin