blown rectifier diode

[Glenn Roberts]

One of the rectifier diodes went on my H-8.  On the 18V supply line.  Made quite a bit of smoke!

 

It’s a 1N2071.  Doesn’t seem to be a readily available part today.  Anyone replace one of these?  What’s a good substitute?

 

-          Glenn

 

[Dan Emrick]

Hi, Glenn,

It appears that the 1N2071 is a 600 PIV version in the 1N2069 series
of 750ma diodes (although the Heath schematic says the 1N2071 is a 1
Amp diode). I think that any of the 1 amp diodes that will fit the
space (I don't have an H8) that has around a 600 PIV rating will
probably serve. I suspect Heath over engineered the PS anyway. It
may be as simple as a trip to the local Radio Shack. If not, someone
may have a scrap PS they can cannibalize for you. On the H89 PS
1N2071s form the diode bridge of the +65V supply as D109-D112.

I expect you're considering this anyway, but I'd be more concerned
about "downstream" problems such as shorted caps that may have
contributed to the failure.

Dan

[Joseph E McGlone]

1N4005 is a very common diode (600V/1A) that should work. Radio Shack
276-1103 (1N4004 400V/1A) for $.99 should work too. If you want the exact
P/N it may be available from:
http://store.americanmicrosemiconductor.com/1n2071.html?gclid=CPiO49bO-6gCFVJ25Qody0IZRg
for $8.72 each although there is no need to go this way.

Like Dan says it's important to find out if there is a reason for the diode
failure. Shorted caps and inserting a board one pin off are common causes.

Joe

Hi, Glenn,

Dan

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[Norberto Collado]

I had the same issue and I went to Radio Shack and got the 1.5 amps rectifier diodes. I encourage to change all of them.

 

If any of your boards do not have the guide pin inserted please see attached pictures and procedure below to protect the diodes from burning out.

 

Procedure:

Glue a 2 pin jumper SHORT BLK (Jameco – 19141 – BOM Line 32) to protect the board from shorting the -18V and the +18V to the +8 Volt rail and to the Ground rail as shown below. If the +-18Volts rails get shorted to ground then the four diodes on the motherboard will burn-out and will also destroy the +-12 Volts regulators on the Serial Communications board. Please use Gorilla Glue that expands 3 to 4 times; from RADIO SHACK. Please use proper orientation as shown on the picture.

 

Norberto

[Lee Hart]

On 5/22/2011 6:44 AM, Glenn Roberts wrote:
> One of the rectifier diodes went on my H-8. On the 18V supply line. Made
> quite a bit of smoke!
>

> It�s a 1N2071. Doesn�t seem to be a readily available part today. Anyone
> replace one of these? What�s a good substitute?

The 1N2071 is a 600v 1amp diode; a 1N4005 (or for that matter, any
1N4001-1N4007) is a good replacement.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

[Glenn Roberts]

Radio shack was good advice.  They have a 25 pack that has 4001, 4002, 4004 and 4007’s for $3.  Spent a few hours disassembling, repairing and reassembling.  It’s up and running now!

 

Though many of my boards have the blocking spacer a few don’t.  I bet that’s what happened.

 

Thanks all!

 

-          Glenn