Re: WG 6100 upgrade updates & MPSU07 replacement.

On Sat, Apr 9, 2011 at 8:40 PM, David Shoemaker <davids@oz.net> wrote:

> I found a update / repair guide for the WG6100 on
> http://www.pinrepair.com/video/wg6100.htm but it was last updated in 2000
> and it mentions some parts that are now no longer available.
>
>
>
> In particular it recommends upgrading the MPSU07 with NTE49. Neither of
> which is actually still in production.
>
>
>
> The net mentions a CENU07/57 replacement but that is also discontinued.
>
>
>
> Looking over my vectorlist archive I see suggestions of:
>
> MPSU07 -> ZTX653 or TIP32C
>
> MPSU57 -> ZTX753 or TIP41C
>
>
>
> But nothing was definitive in those discussions (primarily about the speed
> of the TIP’s and the 1W base limit of the ZTX part).
>
>
>
>
>
> So is there a “new” version of the update guide out there which covers the
> modern replacements? Or has anyone done long term testing of either the ZTX
> or TIP solutions?
>
>
>
> Thanks,
>
> David
>

Way back in 2002 I wrote this, you could use it as a starting point:

Uniwatt transistor availability and cost getting you down?
Looking for better parts at lower cost??
Not scared off by the fact that pinout and heatsink mounting will be
different???

WELL I HAVE A DEAL FOR YOU!

But, seriously, here's what I did. I went to DigiKey, used their
transistor selection capabilities, sorted the results by PRICE, and
tried to find inexpensive replacements.

First, the NPN transistor:

        MPS-U01, MPS-U05, MPS-U06, & MPS-U07 can all be replaced with a
2SD1264
at a cost of $.89 each, DigiKey part number is 2SD1264A-ND. Buy 10 for
$7.42 or 100 for $59.33. (Too expensive? All except the MPS-U06 &
MPS-U07 could be replaced with the 2SD2374 at $.77 each/ 10 for $6.45/
100 for $51.59).

But, you say, what about PNP transistors?

        MPS-U51, MPS-U55, MPS-U56, & MPS-U57 can all be replaced with a
2SB940
at a cost of $.97 each, DigiKey part number is 2SB940A-ND. Buy 10 for
$8.06 or 100 for $64.49. (Too expensive? All except the MPS-U56 &
MPS-U57 could be replaced with the 2SB1548 at $.85 each/ 10 for $7.09/
100 for $56.75).

Of course, as always, I could be completely full of it, but they look
like they should work. And, of course, I have no way to test this
myself. They handle over twice the power and way more current, but the
pinout is different (so careful lead bending will have to happen to
install them) and the old heatsinks might not fit. If the old heatsink
have a mounting hole they should be able to be screwed to the new parts.
Part of what I was trying to do was to keep it under $1 per part. As
good a criteria as any. Somewhere I have several hundred TO-220 heat
sinks, maybe a package deal could be made? (Uniwatt transistor used a
modified TO-202 case with a thin extended tab that sticks out of the
case. The transistor style of choice these days is the TO-220 which has
a thick metal tab that is the entire back of the case. This allows the
transistor to handle way more power and run cooler than the TO-202).

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Received on Sat Apr 9 21:59:12 2011