I used to work for a company (ARCO Oil) that used a bunch of those. Weller
closely guarded their schematics and even now they will not release them.
We sent them in for repair but they charged about as much as to buy a new
one. Here is what I found over fixing a dozen or so.
1) The wire nuts came loose inside
2) Intermittent wires in the cable going to the soldering iron. Flex the
cable while ohming end to end.
3) The surface mount electrolytics go bad. These were MOST of the failures
and I ended up changing all of them in the rest of the 25 irons we
used over about 3 years.
4) The cheap temperature set wire wound pot gets worn out.

Most of the parts in this unit are consumer rated parts and are available.
Never had any problems with the ceramic boards in the units or with the
printed resistors on them. Had a couple of chips fail. It's an A to D with
a seven segment driver built in. They are available still.

Other than the above, they are really a darn good soldering iron and keep
the tip temperature regulated fairly closely.

I still have 2 of them so if you decide to throw them away, send them to me
and I can use them for parts to keep mine in repair. I will reimburse you
for your shipping.

I have more info If you need it.

Rich Klesstinez
3728 Crestline Rd
Fort Worth Tx 76107

Email:
(my name, lower case, no spaces) at charter (dot) net



"Ralph Mowery" wrote in message
...

"RFI-EMI-GUY" wrote in message
...
I have same model unit with same exact problem. Yest it does regulate the
temperature. I haven't figured out the display problem either and the
thermistor in the iron seems to "ohm out" properly. Let me know what you
find. I never could find schematics for it. I used it just today on a PIC
project. Shame to throw it out, but I would like to read the temperature.

--
Joe Leikhim K4SAT

I found several schematics for different models. Never did find the one
that matches mine. I opened it up and it seems there is a ceramic board
with surface devices on it. Almost no user replicable parts. Atleast for
my skill level. I was hoping it would be the discrete parts. I can work
with them. Oh well, it was free and is a good soldering iron even without
the display. I do have a couple of spare parts for it also.

de KU4PT