[jan-jaap]

I use T15 tips from hakko on an FX-951, the only ceramic tip technology is my hakko desoldering gun.

Hey, turns out I have exactly the same. Couldn't be more happy with it. Got some more tips the other day. I thought T12 was for the US and T15 for Europe though?

My desoldering station is Chinese, but it does the job. At least it doesn't clog up all the time.

[weblacky]

I use T15 tips from hakko on an FX-951, the only ceramic tip technology is my hakko desoldering gun.

Hey, turns out I have exactly the same. Couldn't be more happy with it. Got some more tips the other day. I thought T12 was for the US and T15 for Europe though?

My desoldering station is Chinese, but it does the job. At least it doesn't clog up all the time.

Supposedly it’s the other way around. T15 is for USA & EU. But some hand pieces only work with one tip type or the other. 

https://www.eevblog.com/forum/reviews/wh...ries-tips/

That being said, most people have confirmed that you can use the tips interchangeably on the iron that comes with that station.

And yes I agree, best soldering station I’ve used in this wattage. While I wouldn’t pretend it’s 100+ watt soldering iron, it does a great job of knowing when it needs to deliver heat at most of the tips sizes. I also have the micro soldering handpiece and two micro tips for this station as well which I’ve only used a few times but when I’ve used them they’ve done a great job. I tend to use a beveled hoof tip, a drag tip, and two different sizes of chisel tip with this station. It’s never let me down. However I’m also someone who religiously cleans their iron tip during usage and recoats it for storage. I have yet to have a problem after about 7 years so far. 

I know there are a few mods for this station but I’ve never found instructions good enough to follow. I do wish I had the pushbutton mod to not have to use the card key to change temperatures. But I haven’t found instructions so good that I couldn’t screw them up on how to do that.

[weblacky]

Okay, some movement on this old topic...

I went ahead and took the power supply out of my oldest (problem PSU) tezro and rebuilt it using EXACTLY the same capacitor inventory I used on the first one. The result....

SAME...that's right...exactly 3.3v, exactly 5v, and 11.4v for 12V...WHAT!!!!!! Adjusting the same 12V feedback POT I got it up to 11.9v...so.

A completely different PSU, from a very different machine, from a very different environment...same low voltage on the 12V rail result. So the odds are, it MUST be me, my rebuild has done something. I've done a basic go through and I have one more original Tezro PSU I can look at. But looking back on my notes there is only ONE discrepancy in my order list. Digikey was out of 3300uF 10V Nichicon Caps so I ordered 3300uF 16V Nichicon Caps instead. These sit directly on the DC OUTPUT lines...so that's my only thought at this time. There are many caps but there are only 3 of these caps involved in the mix with other low rated caps as well (6.3 & 10v).

I was lead to believe I could substitute higher voltage caps at the same capacitance to lower voltage ones. I can't find any real info that claims a circuit should change with higher-rated caps... however it has been suggested that that rating and the capacitance AT a voltage isn't guaranteed. That is to say the capacitance may be different at a lower voltage than when the same cap is charged at the rated voltage? But I didn't think this was a thing...

Perhaps outside the 20% error margin? I really don't know and right now I'm grasping at straws but so far everything else was SPOT ON for the values I removed...except these substitutes.


So I've ordered 12 new 3300uF 10v Nichicon UPS series caps from DigiKey and will go ahead and install them in place of the "upgrades" I put on the output filters...and see if by magic the 12V output rail magic rises by nearly a volt. Seems flimsy to me...so something IS HAPPENING and this is the only part I've yet found that was changed from the original caps I took out.

Again if someone could explain how a cap with the SAME stated capacitance but with a HIGHER RATED VOLTAGE would affect the DC output (filtering) by lowering the output by half a volt or slightly more...I'd be grateful because right now...that isn't supposed to happen.


It also seriously possible that the caps I got just have a wrong ESR or have a poor charging time and so they don't fill up fast enough reach peak output and therefore rob me of a several tenths of a volt on the DC output?

These caps ARE connected (in some way) to the 12V output line...so they are in the equation, somewhere.


I'll pop them in as soon as I get them but likely that will be late next week. So hang tight, if I find replacing these jumps me BACK into my range, then that's the answer and I'll finish the rebuilds and start looking into doing some measurement for the 1.8v VRM issue and doing a test run after 11 years on the shelf!!


With many fingers crossed of course.

[Raion]

That's less than a 10% difference, it probably was just out of adjustment. It's normal to see voltage on a not fully loaded PSU be a bit out of adjustment.

[jan-jaap]

These sit directly on the DC OUTPUT lines...so that's my only thought at this time.  There are many caps but there are only 3 of these caps involved in the mix with other low rated caps as well (6.3 & 10v).

I was lead to believe I could substitute higher voltage caps at the same capacitance to lower voltage ones. I can't find any real info that claims a circuit should change with higher-rated caps...

I have done exactly this in my PowerSeries PSU rebuilds. I didn't even use the original brand or series (they are thoroughly obsolete).

The PowerOne PSUs are special in that every module (voltage rail) has it's own independent galvanic isolation, and then of course it's own rectifier diodes, coils, snubber and output capacitors. Output voltage is regulated using feedback to the primary side (likely adjusting PWM duty cycle into the chopper FET). Output capacitors only serve to filter output voltage.

Now, these PSUs date back to the late eighties / early nineties. Replacement caps with identical ratings are relatively tiny and leave a lot of space open. At the same time, if you go up 1 step in capacity and 1 step in voltage, you're more or less back to the old size, but have significantly lower ESR and higher ripple current capability. These output caps basically turn half a sine wave into DC so they suffer. I figured that if (1) current generation caps are better to begin with, (2) I replace caps with ones of improved spec, and (3) I only run these systems occasionally, then I probably won't have to do this again in my lifetime. So, e.g. in a 250A@5V module I replaced a bank of a dozen Chemi-Con SXF, 3900uF 10V capacitors with Panasonic FR, 4700uF 16V.

I only upped values of output filter caps. Everything else is the same.

Did you apply a couple of amps of load? PSUs often need at least some load before the regulation works properly.

EDIT: here's part of the replacement chart of the PSU of my 4D/380 VGX to illustrate. Basically 1 row original part, next row(s) with same 'ID' possible replacements, my choice in green.

[weblacky]

In response to the “did you load it” questions. While that would be perfectly valid for any other SGI PSU. I did do it before on my first attempted PSU, that had  this symptom @ 2A on 12v and 2A on 5v using the molex connector while hooked to my 24-pin ATX tester, zero change. So I did not do it this time because these are modern ATX PSU units.  They should not need any external load for basic regulation. Otherwise they wouldn’t sell clip-on testers for the past 10+ years for the ATX 24-pin standard to bench-test basic start and run. Which it what I use on these, just like a modern PC builder.

I had to run out the feedback adjustment to 100% to get what I got.  In both cases it basically went 0.8v or more lower than at least what it should have been before my rebuild.

So while after this 100% run out I am inside the spec, I’m not very well inside the spec to me.

#1. End of molex plug tends to be an additional 0.1v drop to the peripherals.

#2. Recovery from instantaneous change in loading (while system is running) could be suspect in that since I could be like 11.7v and another 0.5v drop due to sudden loading and then I’m scrapping the 10% region 10.9v).


If I have to, fine, but they weren’t like this before, I only fiddled with electrolytic caps l, all of them, even the ones on the control daughter cards. 

I have a “better” condition (final) Tezro PSU that I can use for Huntron comparisons before a rebuild as my final straw. 

I don’t want to have to do that but it seems the factory adjustments were already using up ~3/4 of the 12v adjustment POT.  So when it went down FURTHER that only left me a small amount of adjust left to climb back up to 12v. 

Right now all I have is the “higher rated” three 3300uf cap that are in fact on the 12v rail!  So I assume something like they are actually too big (capacitance) at lower voltage for my output filtering or they charge differently and maybe don’t complete fast enough and leave a small amount of potential filtering output out? 

I’m grasping here, my cap order is scheduled for delivery on Thursday so I’ll be swapping those three caps out when I get it and then I’ll know if I was right to do that or if it made no difference. 

If no difference can be seen then I’ll have to do an exhaustive comparison on my last unit and hopefully find out what has slipped tolerance. 

I’d rather be like 12.2v than be 11.8v due to the voltage drop I know will occur at system use. 

But they aren’t ruined, but I also don’t want fix PSUs, then have rank their feedback up to 100% over factory and then say that’s okay, It’s not with me.

[weblacky]

Okay, Well the hail mary didn't work.

Replacing the three upgraded caps with better exact look-alikes made no observable difference.

I also took the time to purposefully measure, record, fiddle, and reset ALL the other POTs I could find. There is one near the optoisolators that didn't do anything to the output DC voltage (was hoping for feedback adjustments) and the lowest 101 POT also adjusted nearly 25% increase...did nothing to the output voltage.

I set them all back to their measured values just to ensure whatever they do, they are doing it....


So I have only two more ideas until I'm totally out of my depth here.

Idea 1: I have one more (should be working) Tezro PSU. I can bench start it and record values, then I can replace ONLY THE OUTPUT caps and the filter cap...then start it and observe values. If there is NO CHANGE in pre-rebuild vs rebuild values (and they are good) I'll have narrowed it down to the logic daughter boards and small caps on the PFC area and such. If there IS A CHANGE then I know it's either the filter cap (unlikely) or (more likely) the output cap selection.

Idea 2: forget any fiddling with the last PSU and try a exhaustive huntron probing to see if I can find any substantial difference in impedance between the two units. This could be a real rabbit hole as there's a huge amount of combinations one could try. However to try to make it easier I could just probe at the backsides of the PCBs at first to just region Identify quickly without having to really take them apart and splay them out.





There are no other adjustments to fiddle with.

Also I loaded down the 12v line with 3A and the 5v line with 4A while on the ATX tester I have. The values didn't increase or change on the tester...however once loading began on the load tester registered 4.88v = 5v and 11.78v= 12v...multimeter agrees at the ATX 24-pin (back probe).

I find this odd because when the voltage changes (via POT adj) it does update the ATX tester LCD...but under load the ATX tester values don't seem to change while all the other wires register the voltage drop due to load...so not great. Still low but again within range...however I'm unsure if more load= lower which is then a problem.


I also confirmed the voltage DC output rails don't have a short or a shorted diode as I shoved DC power up them (same polarity) and they drew nearly nothing. So no damage on the LV side I can find.

[weblacky]

Okay so I know I've not made headway on this in a while...but...a new hope!  I bought a fair-priced OEM Tezro PSU (claimed working) from Mashek via eBay.

I got it a few days ago and I just got to it now and did the same ATX tester hookup and...

   

Same thing,   even slightly worse! So the good news is, I didn't ruin the previous PSU rebuilds...they do this, it's normal for them.  There MUST be a change that happens due to their unique feedback (connector) mechanism, I guess.  So with that I'm going to start finalizing the PSUs I've repaired (zip ties, RTV stabilizer adhesive, markings, etc) and see about getting back into that.  I still have a single rebuild's worth of Tezro PSU components.  So I'll likely plan to do it again and perhaps one more time.  

But this is good news, I've been stewing on this for some time! 

So now it's proven and known, Tezro OEM PSUs will present with low (just out of ATX spec) 12V on bench testing (I've seen between 11.1v to 11.4v).  I've never gotten a way to clip in a load on the 3.3v rail to see if that changes things, but a 5v and 12V load DOES NOT change the output voltage (I can tell you that because I've load tested on the molex power connector for the drive bays, changes nothing).

I still have a Tezro with the 1.8v slump during startup to look at...I'm convinced it failed due to poor PSU regulation, but I'm NOT convinced fixing the PSU fixes the issue, it's the VRM circuit that's damaged on the mainboard. So Investigating that will be delicate and somewhat dangerous, due to having to separate components and the price of replacing anything due to damage incurred by my disassembly.   Not really looking forward to doing it...but it does NEED to be done.

More to come.