Pace ADS200 soldering station

[mbless]

Here is my latest effort. I'm leaving for the weekend, so I wanted to post this so people can think it over.

I have traced out almost all of the tracks. There are a few vias that disappear into the inner layers, so that'll take some time to figure out if they actually go somewhere I haven't mapped yet. I also need to clean up the op amp and heater drive schematics.

[Cliff Matthews]

Hope Aaron doesn't pop a head-gasket on those schematics.. 

[drojf]

The ADS200 is on 'sale' at Mektronics, so now the price is $499 (excluding GST. Was $543 previously).

PRICES BELOW EXCLUDING GST (i'm pretty sure element14 also excludes GST, correct me if I'm wrong)

Mektronics, with ISB: $499 ('sale')
(Not available yet!) Element14, with ISB: $481
(Not available yet!) Element14,   NO ISB: $435

edit: Mektronics has an ebay account, where the ADS200 costs $576.35 inc GST and free shipping. You can use the PENNY5 discount code to get it for $547.53 inc shipping (or any other ebay voucher you happen to have).

[mbless]

It's for uhh.... educational purposes only 

[labjr]

Hope Aaron doesn't pop a head-gasket on those schematics.. 

I can't imagine someone making a station of the same quality and support for less. Though, I suspect it won't be too long before someone makes a drop-in replacement PCB with a fancy OLED display and custom firmware. Probably increase sales if it becomes a popular unit to mod.

[labjr]

BTW TEquipment has lowered the price of the ADS200 with ISB stand to $243.80 

[Shock]

BTW TEquipment has lowered the price of the ADS200 with ISB stand to $243.80 

Tried the EEVblog 6% off discount code on top of that? Should work as I think they honor it on almost every other deal.

[mbless]

I finally got around to looking at this again and doing some measurements. There is just one via that I can't tell if I found where it went or not. I had to use the 4-wire probes to figure out the current shunt circuitry as the previous iteration didn't make sense. I have a couple of observations/questions about the design.

1. The MCU reset circuitry is rather complex especially considering the data sheet just suggests connecting a cap to VDD.
2. There is a good 0.4V sag on the 5V power rail while the heater is on. The sag is seen in the digital signals. I'm a bit surprised by this since there is the 1000 uF cap. Edit: It's only 20mV. I had a grounding issue.
3. Why have a flip flop control the PNP which controls the NPN which in turn controls the P-channel for heater power? Why not have the flip flop drive the NPN?
4. There is a NTC thermistor in the hand piece just below the bottom of the cartridge. I assume this is for cold-junction compensation. I haven't worked out the LM317 is doing with the thermistor, though.
5. I don't see where/how the current shunt is actually used to measure cartridge current. The op amp circuit doesn't permit it, and the multiplexer is usually passing the cold-junction analog signal while the heater is on, not the thermocouple/current shunt signal. I actually got the over current error message when I accidentally shorted the 5V and ground rails while probing.
6. Concerning the large temperature jumps shown in Dave's video, the only time I see the thermocouple voltage jump is when the heater is on which is expected for a series heater and thermocouple. I would not expect Pace to be making temperature measurements while the heater is on. While the heater is on for an extended period of time, e.g. turning on for the first time, the multiplexer does pass the thermocouple analog signal to the ADC so perhaps Pace does make thermocouple measurements which would cause the temperature to jump. 

[labjr]

2. There is a good 0.4V sag on the 5V power rail while the heater is on. The sag is seen in the digital signals. I'm a bit surprised by this since there is the 1000 uF cap.

That's surprising. How low does the VAA +30V supply go when the heater is on?

[mbless]

2. There is a good 0.4V sag on the 5V power rail while the heater is on. The sag is seen in the digital signals. I'm a bit surprised by this since there is the 1000 uF cap.

That's surprising. How low does the VAA +30V supply go when the heater is on?

Off the top of my head I measured ~32V unloaded and 30V when the heater is on. I am going to remeasure all of the rails tonight since I have my doubts about something. I will update later.

[Cliff Matthews]

Matches my unloaded numbers. ANSI 120VAC can go as high as 126V (too close for comfort with 33.5v on 35v cap). Marco Reps says there's drop-in switch-mode parts for the 7805.. Would switching noise play well with the ICL7660 and op amps?

BTW, my 7805 is 30c cooler now.. 

[mbless]

Matches my unloaded numbers. ANSI 120VAC can go as high as 126V (too close for comfort with 33.5v on 35v cap). Marco Reps says there's drop-in switch-mode parts for the 7805.. Would switching noise play well with the ICL7660 and op amps?

BTW, my 7805 is 30c cooler now.. 

Yes, 35V is too low. Today I measured 33V unloaded and 31V loaded. Plus it is right next to the large heat-generating 7805 .

I personally wouldn't change to an switch mode without a linear post regulator due to noise concerns. I remeasured the 5V rail and got about 20mV drop while the heater was on. I had a grounding issue before that was showing much higher voltage drop.

[Cliff Matthews]

Matches my unloaded numbers. ANSI 120VAC can go as high as 126V (too close for comfort with 33.5v on 35v cap). Marco Reps says there's drop-in switch-mode parts for the 7805.. Would switching noise play well with the ICL7660 and op amps?

BTW, my 7805 is 30c cooler now.. 

Yes, 35V is too low. Today I measured 33V unloaded and 31V loaded. Plus it is right next to the large heat-generating 7805 .

I personally wouldn't change to an switch mode without a linear post regulator due to noise concerns. I remeasured the 5V rail and got about 20mV drop while the heater was on. I had a grounding issue before that was showing much higher voltage drop.

Whew..!  I'm glad. Since Pace gifted mine, I didn't figure I even had a warranty (especially now with all my mods)

Trivia: This Pace is so dedicated, it works during severe brown-outs.. in fact, it can solder at 33% of normal mains 

[labjr]

Trivia: This Pace is so dedicated, it works during severe brown-outs.. in fact, it can solder at 33% of normal mains 

I don't see how that's a selling point. I've never experienced a brown-out while soldering. If I did I'd be in the dark, most likely trying to disconnect anything of value from the mains.

[Shock]

I personally wouldn't change to an switch mode without a linear post regulator due to noise concerns.

Have a look at Recom DC to DC converters they have low noise replacements for the 7805.
This is the one I was looking at (for another application) but they do them in higher input voltages as well.

R-785.0-0.5
https://mouser.com/datasheet/2/468/R-78xx-0.5-958374.pdf

[Cliff Matthews]

Trivia: This Pace is so dedicated, it works during severe brown-outs.. in fact, it can solder at 33% of normal mains 

I don't see how that's a selling point. I've never experienced a brown-out while soldering. If I did I'd be in the dark, most likely trying to disconnect anything of value from the mains.

That was humor (based on Vin/Vout that 7805 has to drop..) 

[In Vacuo Veritas]

Wow, did treez design that thing? Looks almost improvised.

[Cliff Matthews]

Wow, did treez design that thing? Looks almost improvised.

That's a compliment.. isn't he due to finish primary school soon? 

[Cliff Matthews]

Testing driving 1.3 firmware today, display update's smooth (no more hi-lo or too fast to read stuff). I can clearly read overshoot-undershoot values, but even soaked sponge-dunking, it's not off by more by 12c during a 2 second recovery.

[Cliff Matthews]

Update. During the last week I caught a glimpse of chatter between beta testers and responsiveness of the software team. I even had a nit-pick over ISB wake-up and Pace included that too. I don't know when I'll receive my next PLCC, but they do listen 

[PACE-Worldwide]

Update. During the last week I caught a glimpse of chatter between beta testers and responsiveness of the software team. I even had a nit-pick over ISB wake-up and Pace included that too. I don't know when I'll receive my next PLCC, but they do listen 

Cliff,

They'll be an update probably by early next week, so you should receive a new PLCC Chip (and chip puller) by the week after.

Aaron

[Cliff Matthews]

Update. During the last week I caught a glimpse of chatter between beta testers and responsiveness of the software team. I even had a nit-pick over ISB wake-up and Pace included that too. I don't know when I'll receive my next PLCC, but they do listen 

Cliff,

They'll be an update probably by early next week, so you should receive a new PLCC Chip (and chip puller) by the week after.

Aaron

Aaron I'm not so concerned for that update.. I am more concerned for Pace families braving the arrival of Hurricane Florence!
Please take care down there!

[Bud]

@PACE-Worldwide
When you guys will ship the product that includes this update to distributors? Is it another couple months?

[PACE-Worldwide]

@PACE-Worldwide
When you guys will ship the product that includes this update to distributors? Is it another couple months?

Distributors are notified and provided with new chips when the updates are officially released. But I'll post a notice here with instructions on how to obtain an update firmware revision (which are provided to existing customers free of charge), probably next week.

Aaron

[Bud]

Honestly i do not believe many distributors would enthusiastically open hundreds of boxes and change the firmware chips, unless they are maybe obligated to do so by contract with Pace.