898D+ Solder Station Repair

[danadak]

I purchased one last Sept, using iron side of station. Then yesterday used
hot air, worked for ~ 1 hour, although fan speed control would not work.
Then hot iron fan failed, overheating in the process. Now totally dysfunctional.

Anyone have a schematic ? Its a no brand knockoff, so I am guessing it follows
the OEM version(s). I have already poked around trying to troubleshoot but
a schematic would be quite useful.

Regards, Dana.

[bitseeker]

Since a lot of these kinds of things can have many variations, it's a good idea to post some photos of the PCB(s), etc. to help folks orient to the device you're inquiring about.

[danadak]

A couple of pics

Regards, Dana.

[nogood]

Is that red stuff on the connectors and IC melted cable isolation or just some sort of paint ?

edit: nvm, I noticed it on the front panel too... glue, duhh

[KL27x]

5V rail: Do the displays turn on? Do they show what they're supposed to? If not then you're probably screwed. Check the voltage on the control board rail.

If it's 0V or 5V, then maybe you're ok. Proceed to look for a loose wire or a cold solder joint. If it's 0V, check the output of the transformer. Check the 5V regulator.

If you get high voltage on the 5V line, then your whole control end is probably fried.

If the 5v rail and the displays are good, look at the power FET/TRIAC and w/e is driving them. If those are fine, check for any problems on the sensor/voltage feedback lines.

Just start at the logical spots. You don't need a schematic to look for the common and/or practically fixable problems.

[danadak]

The red stuff is just glue to hold stuff in place.

The 5V rail is good, solder iron side of station works, shows temp ramping on display and then
level off so control loop OK (I assume micro uses essentially same code base for both sides).

What I do not see is 24 Vdc at fan, when it was working fan was always on when switch thrown.
I did check fan, its hosed.

Contacted vendor, trying to get schematic out of them, to see how 24 Vdc is developed. Trying
to avoid creating a schematic from scratch, looks like I have wasted enough time maybe I
should give up and do that. I detect vendor thinks his schematic part of the nuclear triad arms
race top secrets. People get real weird when they use 2 Rs and an NPN and a load R and create
a 1 transistor amp, they think that is a top secret. I have same problem with an amplified sub
woofer, oem will not provide schematic. Idiots.

Thanks guys for the replies, I will get off my lazy arse and create a schematic from scratch. Ugh.

Regards, Dana.