Really universal soldering controller

A place to document your own projects.

Re: Really universal soldering controller

Postby afedorov » Tue Nov 06, 2018 9:15 am

I've soldered it to ground. But crystals can be easily damaged by overheating, so if you not sure - leave it as is.
afedorov
Full Member
Full Member
 
Posts: 172
Joined: Wed Mar 23, 2016 8:44 am
Location: Russia

Re: Really universal soldering controller

Postby Doomedahab » Tue Nov 06, 2018 3:47 pm

I tried briefly, but the smooth stainless casing is proving hard to solder to. I might try again after maybe sanding the case slightly to make the surface more rough. But for now I will leave it if it's not critical.
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby aimpertro » Wed Nov 07, 2018 10:50 am

I have a couple of 5mOhm WSL3637 shunt resistors lying around. Is it also possible to use this value instead of the 3mR/4mR version as specified in the BOM and scale the appropriate gain resistors accordingly? Or will the power dissipation be too large?

Thanks!
aimpertro
Newbie
Newbie
 
Posts: 1
Joined: Wed Nov 07, 2018 10:46 am

Re: Really universal soldering controller

Postby minkok » Wed Nov 07, 2018 12:07 pm

aimpertro wrote:I have a couple of 5mOhm WSL3637 shunt resistors lying around. Is it also possible to use this value instead of the 3mR/4mR version as specified in the BOM and scale the appropriate gain resistors accordingly? Or will the power dissipation be too large?
Thanks!

Definitely doesn't worth. You will have a mess with current and temperature alignment, it will be also nightmare, if you got other assembling problems together with that, for some bucks more and 1 or 2 weeks waiting, you will save much more troubles!
Last edited by minkok on Thu Nov 08, 2018 8:59 am, edited 1 time in total.
minkok
Full Member
Full Member
 
Posts: 144
Joined: Wed Jun 21, 2017 11:54 pm

Re: Really universal soldering controller

Postby Tony » Wed Nov 07, 2018 1:16 pm

Hi, aimpertro

Yes, R37, R43 2.5K for 5mOhm WSL3637 will be OK. You must use 0.1% resistors.
e.g. 2mOhms not recommended.

Tony
Tony
Newbie
Newbie
 
Posts: 16
Joined: Sun Mar 11, 2018 12:04 pm

Re: Really universal soldering controller

Postby minkok » Thu Nov 08, 2018 8:58 am

Tony wrote:Hi, aimpertro
Yes, R37, R43 2.5K for 5mOhm WSL3637 will be OK. You must use 0.1% resistors.
e.g. 2mOhms not recommended.
Tony

Hello Tony, when I built mine, even I had 3mOhm WSL3637, the temperature alignment was outside of pot Rc2 regulation.
How was yours?
Anyway, the current function over shunt is linear, but did you measure the max current, or at least Vshunt and compare it to display readings?
minkok
Full Member
Full Member
 
Posts: 144
Joined: Wed Jun 21, 2017 11:54 pm

Re: Really universal soldering controller

Postby Doomedahab » Thu Nov 08, 2018 5:30 pm

Ok, so tonight I tried to power up the back board. It turns out that my toroidal transformer actually puts out 27.2 volts at 238V mains voltage. Is that to be expected for a 230v, 120VA, 24v transformer?

Anyway, I connected the board to the transformer, and unfortunately I do not get correct readings when measuring at J3. between the 3.3 pin and gnd i read 0.02 volts. Not good.

Some measurements I took:

across the TVS: 11.42V
across the diodes: 14.98V
C1: 11.52V
I tried a few other C's but they read fractions of volts at best.

Can anybody give me some advice as to where and what to measure next to find the root cause?

I did have to solder Q2, Q8 directly to the vias (see a page back), but they do not appear to be shorted when doing a continuity test. would these mosfets be a possible cause of the bad readings?
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby minkok » Thu Nov 08, 2018 11:23 pm

Hello Doomedahab,
first disconnect the front board and check again C1 voltage and if it the same, check fuse, if D1 to D4 are correct positioned, if you connect Trf. to J1 and remove TVS temporary to measure Vc1.
minkok
Full Member
Full Member
 
Posts: 144
Joined: Wed Jun 21, 2017 11:54 pm

Re: Really universal soldering controller

Postby Doomedahab » Fri Nov 09, 2018 8:34 am

minkok wrote:Hello Doomedahab,
first disconnect the front board and check again C1 voltage and if it the same, check fuse, if D1 to D4 are correct positioned, if you connect Trf. to J1 and remove TVS temporary to measure Vc1.


Thanks Minkok!

All measurements were without the front board attached. D1-D4 are oriented correctly. I already inspected the fuse, and replaced it to be sure. The fuses look undamaged. It's a clear glass version with a thin wire so it would be easy to spot if it would have popped. There is however virtually no voltage across its terminals.

I will remove the TVS tonight and re-measure C1
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby Doomedahab » Fri Nov 09, 2018 2:26 pm

Without TVS voltage across C1 is 11.53V, no difference.

Q2: 10.95V
Q8: 8.46V
Q10: 0.2V
Q11: 1.64V

Q10 seems suspect?

Edit: Q12 reads 11.6V
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby afedorov » Fri Nov 09, 2018 9:55 pm

Doomedahab wrote:Without TVS voltage across C1 is 11.53V, no difference.

Q2: 10.95V
Q8: 8.46V
Q10: 0.2V
Q11: 1.64V

Q10 seems suspect?

Edit: Q12 reads 11.6V

Measuring voltages before D6 with DMM is pointless - there is unsmoothed rectified AC voltage. Do measurements on cathode of D6 and on C6. Be careful around U1 as probe could easily slip and short Vin to 3.3V rail.
Did you connect the transformer to AC connector? If it's connected to DC one, you'd only have a half-period and a half of input voltage.
afedorov
Full Member
Full Member
 
Posts: 172
Joined: Wed Mar 23, 2016 8:44 am
Location: Russia

Re: Really universal soldering controller

Postby minkok » Sat Nov 10, 2018 12:32 am

Doomedahab wrote:Without TVS voltage across C1 is 11.53V, no difference.

Q2: 10.95V
Q8: 8.46V
Q10: 0.2V
Q11: 1.64V

Q10 seems suspect?

Edit: Q12 reads 11.6V


If you checked " if you connect Trf. to J1" ,

do follow without connected Iron: without power, check D13 and C17 and/or remove them temporary and check Vc1
p.s. check also for correct position of D13
minkok
Full Member
Full Member
 
Posts: 144
Joined: Wed Jun 21, 2017 11:54 pm

Re: Really universal soldering controller

Postby Doomedahab » Sat Nov 10, 2018 3:58 am

Afedorov, Minkok: thanks for the pointers. As you will have guessed I am dependent on experts like yourselves to point me in the right direction, so thanks again so much!

I am connected to AC, so that's not it. I will follow up on your tips and report back. I'll post some pictures too.
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby Doomedahab » Sat Nov 10, 2018 7:58 am

So now I removed c17, d13. D13 was oriented correctly by the way. Across their terminals I measure 9.4v.

D6 is 11.61v

C1 11.45v
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

Re: Really universal soldering controller

Postby Doomedahab » Sat Nov 10, 2018 8:11 am

Here are some pictures
Attachments
1541855261012410.jpg
1541855261381151.jpg
1541855261582585.jpg
1541855260340717.jpg
Doomedahab
Newbie
Newbie
 
Posts: 24
Joined: Sat Oct 20, 2018 3:03 am

PreviousNext

Return to Project logs