Pace MBT350 - Transformer Conversion from US to EU - Page 1
Forum section: electronics / general

author: rev3rse
author_rank: Contributor
timestamp: April 10, 2025, 10:07:18 am
content: Hello Everyone,I scored an MBT 350 from Ebay - a few weeks ago, from US - together with a pair of a hot tweezers, and stand for it for 149USD (the shipping and inport was about the same as the product ... being from US but ....) It just arrived yesterday.I was using Pace soldering tools for over 20 years, and I am really happy I finally got one of these. I will also stick to Pace, also a reason being that I have a very large collection of direct heating tips gathered over the years (over 40 - 50 pieces of different sizes and shapes).I have on my bench a ST50 with at TD-100A and a ST75 with a SX-90 solder sucker. I never had a pair of hot tweezers. I replaced both units with this one and I couldn't be happier. Everything works nice.Since i've done some service on my ST75 pump in the past, i've noticed that Pace is using the same transformer for all models (even the ST50) - but has a dual winding on the primary. For European models, they just hook them up in series, and for US models in parallel. So I just opened the new MBT350 and re-wired the transformer's primary winding in series like this: BLACK and BLUE - AC 230 MAIN, and tied together WHITE and BROWN.I measured the output voltages and they seem fine, 22V and 16V. I arranged neatly everything back together, cleaned and neatly cable tied everything inside, and used hot shrink on my job. I also ordered from TME new fuses - 1.25 Amp / time delay, the original being 2Amp.Thankyou for your time and help,Popte.

author: djsb
author_rank: Super Contributor
timestamp: April 10, 2025, 11:07:34 am
content: Could you provide a quick sketch/schematic of how you have wired the primary windings together, please (which colour of wires connect together)? I have the same model that is wired for 115V, and I'm using a 230V to 115V external transformer. As I need to replace the LCD anyway, I may as well rewire it for 230V. Thanks.PS It would be great if someone could confirm that the phase of the connections are correct or do they need reversing? Thanks.

author: rev3rse
author_rank: Contributor
timestamp: April 10, 2025, 11:22:49 am
content: Please see picture 2 with the transformer label.I wired: BLACK and BLUE - AC 230 MAIN (Blue outlet, black comes from the front switch)WHITE and BROWN. Tied together.The same wiring is from factory on my ST75's transformer AND my ST50's transformer (both "E" version - for Europe).Popte.

author: rev3rse
author_rank: Contributor
timestamp: April 11, 2025, 07:53:13 am
content: Good Morning David,Quote from: djsb on April 10, 2025, 11:07:34 amFor the sake of completion, last night I opened my Pace ST75 again.Below you can see a picture of the transformer label. It's exactly the same (different power ofc.). Same colors, exactly the same wiring. I did some research about this, and to answer my own question and doubts, yes it's correct. "dot to non dot connection" of the primary windings. Otherwise the transformer would have blown or I wouldn't have the correct voltages on secondary outputs if primary windings would cancel each other. So I can confidently say YES it's correct.Also ... I removed the labels from the back, and made new ones, using as a guide a picture of the European version of the station - to match the voltage and fuse ratings. You can download the PDF below - when printing make sure you pick "Actual Size" in Acrobat Reader. I printed them on RayFilm (printable mate silver sheets) and they look exactly like the original.https://www.rayfilm.cz/e-shop/select.php?detail_search=4&skupina=-10&9amp6803amp1=R0555https://drive.google.com/file/d/12x_jaNsAh4BtXLIB-GxhTlZPLqRwxE1f/view?usp=drive_linkPlease remember to REPLACE the FUSES (there are 2 in the back, 1 is spare). 1.25 Amps seems a bit much but the official Pace MBT350 manual lists 1.25A slow blow fuses as spares for European Version.I bought these:https://www.tme.eu/gb/details/02151.25hxp/fuses-5x20mm-time-lag/littelfuse/EDITThe fuses arrived and THEY BLOW instantly because of the inrush current. Being a thoroidal transformer, I considered to add a thermistor to limit the inrush current, but I gave up the ideea for now - because I don't consider this an "elegant" solution. An inrush limiting resistor with a parallel relay circuit would be better if needed (I will consider that in the future).I noticed the fuses that I've purchased sustain 10x rated for 150miliseconds. (10In: max 150ms), and I ordered some with 10In: max 300ms, hoping that they won't blow during startup, and they resist the inrush. The order didn't arrive yet to give feedback.https://www.tme.eu/en/details/0034.5044/fuses-5x20mm-time-lag/schurter/EDITThe fuses are working fine. Tested multiple times. They withstand the inrush current and they work fine.Popte.

author: Shock
author_rank: Super Contributor
timestamp: April 16, 2025, 02:05:02 am
content: What a bargain!

author: djsb
author_rank: Super Contributor
timestamp: April 19, 2025, 05:23:35 pm
content: Popte,I will await your feedback on the fuses. In the meantime, I've started work on my unit. I need to also replace the LCD (a delicate operation that will need great care and a steady use of Chip Quik (or SRA fast chip removal alloy), Goot Wick solder braid (+flux) and my Engineer solder sucker). I've ordered an STTC-038 (for temperature sensitive work) bit for the Metcal at work.I've also asked PACE about a firmware update for the (socketed) chip labelled 1187-0288 Rev:PThe PCB was quite easy to remove, it's the LCD will be a pain as the three main socket need to be desoldered in order to gain access to the LCD pins. I may as well change the pump filter at the same time.I'll have a go at the transformer primary rewiring later.

author: TimFox
author_rank: Super Contributor
timestamp: April 19, 2025, 05:40:12 pm
content: Note on the color code for the primary connections:Black is US code for "line", White is US code for "neutral"Brown is IEC code for "line", Blue is IEC code for "neutral".This is consistent with the connections discussed above for 120 or 240 V.(Somebody complained in another thread when I called the latter an "European code", so I used politically-correct language here.)

author: rev3rse
author_rank: Contributor
timestamp: April 20, 2025, 05:00:16 pm
content: Thanks for the input TimFox ! Useful information that I didn't know. I will keep this in mind.David, you don't need to desolder the 3 main connectors (the connectors for handpieces) !!You should be able to pry them out. The center (black core) - slides out. They are held in place with small clips on either side of the "blue collar". I use a long thin screwdriver for this, and CAREFULLY (don't brake them, don't over-stress them) - prying them and wiggling the PCB while I dod this. I keep the small blue tabs open by placing ... toothpicks in them on one side - while I pry the other side. Works, and i've done this before on ST75 (one connector though ... not 3) and I may soon need to pry 3 on a MBT350 for a screen replacement also (to black on green). Tell us how it went. I will be back with news. I have some packages on the way - but DHL and UPS are taking their time ... because of the holidays.Firefly did the same thing, and in this post you can see the result. trapc45 described the same "extraction" method for the PCB.https://www.eevblog.com/forum/repair/pace-mbt-350-lcd/msg2119711/#msg2119711Popte.

author: djsb
author_rank: Super Contributor
timestamp: April 20, 2025, 06:47:01 pm
content: Where in the attached photo are the tabs and where did you place your long screwdriver/toothpick? Is it on the bits of plastic with the numbers on?

author: rev3rse
author_rank: Contributor
timestamp: April 20, 2025, 07:08:52 pm
content: yes, those are the tabs that need to be pryed a bit. They are not brittle but take good care not to break them.There are also 3 on the other side - so 6 in total . Wiggle the PCB and pry them - and take it out. Everything that's black (the center of the connector) slides out.It will be easy to reassemble. All 3 will click in place.

author: djsb
author_rank: Super Contributor
timestamp: April 21, 2025, 07:17:17 am
content: There were only 3 tabs as shown in the last photo. I used a PCB component lead removal hook from a Hozan H-74 solder aid set to gently pull each tab forward slightly whilst exerting upward pressure on the MBT350 PCB. The board was removed fairly quickly. However, one of the Steel stand-offs became detached in the process. I'll stick it back onto the aluminium panel with some JB Weld. There are still 3 stand-offs secured on the panel so they should be enough. Next to remove the old LCD and put the new one in.

author: rev3rse
author_rank: Contributor
timestamp: April 21, 2025, 08:01:45 am
content: Glad to hear that everything worked out fine !I have a set of ... lockpicks. Those would be a suitabel tool for this job - same tip shapeAnyway, the stands were glued to the front pannel ... so it's not a big deal I guess.You could remove the LCD with a solder sucker - but since the station it's the thing that's being repaired ... I guess the "copper wire method" should desolder all pins at the same time. Should work.When you reinstall the new lcd make sure it's at the same height so it contacts perfectly the front pannel. Someone said here in the post i've linked above that the standoffs and screws needed to be replaced ... but I am not sure about that yet. If the new LCD has the exact same thickness shouldn't be a problem.Thanks for the feedback. Will help me soon with my project.Popte.

author: djsb
author_rank: Super Contributor
timestamp: April 25, 2025, 08:30:54 pm
content: Still working on removing the existing LCD. Got the majority of the solder off the surface pads of the 16 pins. Just got to remove some solder from the bottom layer pins and plated through holes of the LCD.I'll be rewiring the mains primary over the next few days/week.I asked Tony Jones at PACE in Vass, North Carolina USA about the last firmware update for the MBT350 (Version 2.9) and he said that the final updates mainly concerned the correction of minor temperature regulation anomalies. These should not be of any concern for the normal user and would only be required for users in the medical or aeronautical industries. So best sticking with the version you have already.

author: rev3rse
author_rank: Contributor
timestamp: April 25, 2025, 09:51:56 pm
content: Good evening everyone.So, being a hoarder as I am, I bought another. Actually, I submitted a bid on it and didn't really think about it ... won at 221 EUR (delivered). I guess it's starting to rain with MBTs for some reason ...This one looked horrible. The first one I bought looked and worked as new and was made in 2023, firmware 2.9. This one had a shot pump (blowing, not sucking ...). The LCD was replaced, and the contrast was fixed with a resistor soldered to V0 (pin 1 to 3). The LCD is also undersized vertically.It has firmware 1.5, and the differences that I've noticed between 1.5 on this second one and 2.9 on the newer one are- You can adjust the minimum and maximum temperature on each separate channel on 2.9 - one setting is for all channels on 1.5- Setback separate as well on each channel on 2.9 - one setting on 1.5- OS mode setting on 2.9 (for calibration if handpiece or tip was removed) The date code on the pump is 2005 (20 years old? I am old ...).Anyway, I took it apart, and I want you to see the transformer. This old one is a EUROPEAN version, so this wiring was done from the factory. Exactly what I've done on my first one! And it's a "GALAXY" transformerI cleaned and restored everything (including the inside of the pump piston/bore and hoses). Tied everything nicely and neatly. Cleaned up nicely, for what it's worth ...I have a green 1602 display on the way and 2 pump rebuild kits from the USA.Since we are talking about hoarding ... I have the full set of tools for this one also (SX-90, TD-100 and a MT-100) all new. I will use them on the newer one and keep this one as a back-up with the tools in the pictures. And I wanted to show you why I will not switch from Pace to anything else. I have tips for a lifetime, and then some to leave for my kids ...I will keep you updated with this one. Next week - I will complete the restoration, display, pump and all buttons.Popte.

author: djsb
author_rank: Super Contributor
timestamp: April 26, 2025, 09:30:54 am
content: Here is mine with the 2 off 115V/120V primaries rewired in series. I've used Wago 221 connectors to join the white and brown cables. I've also placed a Wago 221 connector on EACH of the brown and white stub cables in case anyone in the future would want to revert the wiring back to 120V. These connectors are secure enough and have really strong sprung terminals enclosed in plastic.Popte, which are your favourite PACE cartridges? Thanks.

author: rev3rse
author_rank: Contributor
timestamp: April 26, 2025, 09:34:38 pm
content: Nicely done David.If you removed most of the solder from the LCD pins ... you could use some hot air to take it out. I took it out on the second station - and I protected the LCD with some kapton tape - hot air was enough to loosen the sweat joints.I do some work (not for a living) on some industrial equipment (fanuc / siemens PLC's and accesories) pro bono for the factory I work for. I am actually working in IT. I use only 60/40 solder, and the equipment I work on is NOT ROHS compliant. In my spare time I refurbish restore and repair vintage computers. Also NOT ROHS compliant. I am telling you this to paint a background for my tip use. I also have a set-back stand for my iron. I do a fair amount of soldering - a few hours maybe 3 days / week, every week. Since 2017 I replaced ONE tip that lost it's iron coating and got eaten to the copper inner layer. They last years in my use scenario. I never use the wet sponge, only the brass wool, and I keep my tips clean and tinned.90 % of the time I do SMD work. so my most used tip is 1124-0047-P1 - that's my go to usually and I find it odd to use anything else after all this time.I have on hand 1124-0003-P1 and 1124-0019-P1 and I am fairly used to them.Since I have so many options, if needed I have anything needed for any job. From very large to 1126 "diamond tips" - chisel or other shapes.I have a tip that I use for "drag soldering" with a "hoof shape" but can't remember the PN - I am using that rarely, I usually do "point by point" soldering even on large packages - still using 0047 mentioned above.For hot tweesers I have 3 sets of tips, but 2 of them stand up. 1124-1001-P1 and 1124-1004-P1. For 0603 I noticed the first one is most apropriate and it stays on the tweesers all the time (1124-1001-P1).For SX-90 I have 2 sets of "sample kits" - 6993-0288-P1 and they do everything I need. I never felt the need to buy a specific tip in pack or five. This diversity gives me options. I cannot live without a desoldering tool, so this is a must for removing connectors with a large number of pins.So to summarise:- soldering 1124-0047-P1- tweesers 1124-1001-P1- desoldering 6993-0288-P1Popte.

author: djsb
author_rank: Super Contributor
timestamp: April 27, 2025, 12:10:16 pm
content: You mentioned that you serviced the pump. Could you give us some details of how you did this in a separate topic please? I know that a pump diaphragm and gasket kit is available from Pace. Thanks.

author: rev3rse
author_rank: Contributor
timestamp: April 28, 2025, 09:57:21 am
content: QuoteI don't think a new thread is needed. It's a simple operation. Just take the pump out (the 3 screws that hold it in place secured in those 3 blue rubber anti-vibration gaskets).Open the lower part (the 4 screws that are underneath the pump in your picture. Those that are on the side with the hoses. The four scews on the side - are from the bearing. I don't see a need to open that up.Clean with IPA all the plastic parts. Clean the diaphagm. Clean the rubber seal, take out the screw in the center of the piston and clean the "ring" and the white bore of the piston.If any of theese parts gets sticky from flux - the diaphragm won't vibrate and cannot pump / suck air. (doesn't close and open on those 2 stages).Put everything back together. The diaphagm cannot be installed the other way around because the 2 centering holes are of different diameter - so it fits one way only (doesn't matter how you flip it). The rubber gasked under the metal cap has a "notch" that must match with the notch on the metal cap.I asked a friend from US to buy me a couple of rebuild sets - since the piston "ring" must be replaced at least. Any amount of cleaning doesn't make up for the wear. But usually in the piston bore, the sticky residue deposits should be cleaned. Also make sure the diaphagm is not sticky.Make sure when you put the screws back (the long ones that hold the assembly) - you don't cut new threads in the plastic. Try to screw them in into the existing thread.That's all. A 10 minutes job. And it does make a difference if there's harneded sticky flux inside.Here you have the manual from pace.Piston Pump Rebuild Kit_EN.pdf(280.42 kB - downloaded 86 times.)Popte.

author: GLouie
author_rank: Regular Contributor
timestamp: April 28, 2025, 05:00:18 pm
content: If the pump is like the MBT250 pump, check the condition of the plastic connecting rod, that connects the motor eccentric to the pump block. Mine broke after 30 years, Pace of course has replacements.I conjecture that the plastic got brittle. I had not done any rebuild of the pump, but see that working on it could also stress the connecting rod.

author: rev3rse
author_rank: Contributor
timestamp: April 28, 2025, 08:19:37 pm
content: QuoteIt's not. It's a different part / pump assembly.Some guy is selling a 3D printed (PETG) connecting rod on ebay.https://shorturl.at/z2xKxHe's saying that :Quote:"It is suitable for the following stations:PRC2000-TH Through Hole Miniature-Microminiature Electronic Repair Station 8007-0138 and 8007-0139MBT250-SD Soldering, Desoldering & Rework System 8007-0203 and 8007-0204Also for early versions MBT-201's with serial numbers prior to 37781"I could design one in SolidWorks if I would have one to take measurements. And open source it.I needed a quick connector for visifilter. Here's my STL and Solid Works part.Pace Fast Nozzle.zip(170.51 kB - downloaded 72 times.)I also needed some stands that look "original". Here's my take on those (STL and Solid Works project):Pace Stand.zip(90.88 kB - downloaded 61 times.)Here are the hose clips for SX desolder pump:https://www.thingiverse.com/thing:5102461And here is the cartridge lock for SX tools:https://www.printables.com/model/1138967-pace-mbt-250-desoldering-grip-for-cartridge-lockI guess any part can be 3D printed nowadays. Or most of them. As long as they are not in close contact with direct heat.Popte.

author: rev3rse
author_rank: Contributor
timestamp: May 07, 2025, 11:27:01 am
content: Hello everyone,So I am done with the second unit (the old one).I replaced:LCD Display: NEWHAVEN DISPLAY INTERNATIONAL - NHD-0216K1Z-FL-YBW - 80x36x13,2mmScrews: KRAFTBERG Stainless Steel M2 x 14mm M2X14/D7985-A2Nuts: KRAFTBERG Stainless Steel M2 x 1.6mm M2/D934-A2Washers: BOSSARD 2,2mm ID x 4mm OD - 8165092Washer: Internally serrated (top) - BOSSARD 2.2mm ID x 4.5mm OD - 1254197Spacer sleeve: DREMEC - Cylindrical; polyamide; L: 4mm; Øout: 4mm; black - 384/2.2X4 (original were 3mm, I eliminated the gap between the front pannel and the screen)Switches: KNITTER-SWITCH - TSS 65 N - 1,6 Newton (1 mm taller - that's not a problem, nice tactile feedback)Snap In Capacitor: NICHICON 10mF / 50VDC 30x50mm 105C - LGU1H103MELB (someone worked on the unit before and managed to scrape it badly on re-aseembly)Capacitor Polymer: Panasonic 10uF; 10VDC; SMD; OS-CON SVP; ±20%; Ø4x5.4mm - 10SVP10M (the 3 SMD caps)LDO: TEXAS INSTRUMENTS - 5V 1.5A LM340T-5.0/NOPB (and soldered in such a position that is farther from the caps, new thermal paste)Everything is perfect. I am still waiting for the pump kits for The USA, but that won't be a problem.Popte.

author: Haenk
author_rank: Super Contributor
timestamp: May 07, 2025, 01:31:36 pm
content: Btw. I have good experience with cutting those filters from unused and expired FFP2 masks. Works pretty well, it seems. And costs nothing (I still have plenty, and it's better use than just throwing them away).

author: rev3rse
author_rank: Contributor
timestamp: May 07, 2025, 06:25:23 pm
content: Quote from: Haenk on May 07, 2025, 01:31:36 pmThanks Haenk ! Great tip ! Thanks alot.Here's one from me - I found (I would share the link but doesn't work anymore) on aliexpress - borosilicate tubes 14mm OD x 11mm ID x 75mm - exactly like the original Pace glass chamber solder traps for SX80 / 90 / 100. They weren't cheap (as in 2 bucks) but for 15 USD I think I got 5 or something. I searched just now and found some but not the dimensions I need. They are selling them for "drink ornamentation" or something ... don't know but the pictures where with cocktails with tubes in them ...Popte.

author: djsb
author_rank: Super Contributor
timestamp: May 07, 2025, 09:28:44 pm
content: Did you find a fuse which works without blowing when the unit is turned on? Thanks.

author: rev3rse
author_rank: Contributor
timestamp: May 07, 2025, 10:21:59 pm
content: Quote from: djsb on May 07, 2025, 09:28:44 pmTry theese:https://www.tme.eu/ro/en/details/0034.5044/fuses-5x20mm-time-lag/schurter/0034.5044SCHURTERAll good with the display / transformer ?

author: Shock
author_rank: Super Contributor
timestamp: May 08, 2025, 04:14:31 pm
content: Well done, looks new. Might as well work on wiring some additional handpieces then you can run 6 channels.

author: djsb
author_rank: Super Contributor
timestamp: May 08, 2025, 06:20:58 pm
content: Thanks for the fuse info.I've just got to remove the remnants of solder inside the plated holes of the LCD. I'm borrowing a Hakko FR-301 portable desoldering gun and an N61-12 Long type nozzle to help. Have you used this yourself?Once I get the old one off the rest should be straightforward. Thanks.

author: djsb
author_rank: Super Contributor
timestamp: May 22, 2025, 07:09:59 pm
content: Removed the old blue LCD. Fitted a new green LCD. Ordered the fuses from TME (10 off) so curious to see how long they take to arrive and from where. This is my first order from TME. Shipping via DHL and should cost around £10.

author: rev3rse
author_rank: Contributor
timestamp: May 23, 2025, 12:48:54 pm
content: TME delivers from Poland. It should take ... 3 - 5 days. My packages get delivered with UPS ground (the cheapest option you get there in the list) and some of them are COD if i want to (but costs extra 1 EUR for COD). Farnell, Mouser or TME - all deliver via UPS to me and they all have the same delivery time (about 4 days).The fuses are OK. Tested. They work for me 100%.Don't solder to "hard" the new LCD. I mean don't solder all the pins "for good". Just tack them with a bit of solder in case you need to remove it later. Just saying....Why ? Because I used a Newhaven display and the contrast wasn't right. You can adjust the contrast in 2 ways if it's not perfect. Either replace a resistor on the back of the LCD either/or/and replace a resistor on the board.I am posting this just in case. I didn't say I managed to release magic smoke from that PWM controlling transistor (don't ask how ...)and I replaced it with a BC807 from Nexperia. And I found out that the resistor next to it controls the contrast. So that being said - I found out that ANY cheap display on the market will work - but since the contrast voltage varies between them (even the same brand) - you can make adjustments.I hope everything works fine from the first try but just in case or if someone stumbles over this post - here's a picture.In the mean time did you test the LCD ? You can use the fuses that are inside now no worries (the 2 Amp ones) - just to see if everything is right and the contrast controls work nicely.Popte.

author: djsb
author_rank: Super Contributor
timestamp: May 25, 2025, 08:02:55 am
content: Good news. The LCD is working OK when powered on. I just need to figure out which way the 6 wire socket (for CH1 and CH2 sockets on the rear panel) should plug into the PCB (see photo attached) and then I can button it up. Just got to glue the metal post back onto the front panel with JB Weld.

author: rev3rse
author_rank: Contributor
timestamp: May 25, 2025, 09:27:30 am
content: Black wires up. Black wires face the top (the display) looking from the top. That way channel 1 and channel 2 set back plugs are not reversed.Seems to be the other way around looking at the picture.

author: djsb
author_rank: Super Contributor
timestamp: June 14, 2025, 03:12:19 pm
content: All buttoned up and working. LCD is much improved and green is easier on my eyes. Not put the new fuse in yet but might try it later. Popte, thanks for your help.