Weller WTP90 soldering iron - Page 1
Forum section: electronics / projects

author: ksilabs
author_rank: Regular Contributor
timestamp: April 04, 2019, 05:42:58 pm
content: Does anybody know what's inside (schematic)? It seems to be the only member of WT line, no other WTxyz products in existence. I have 2 WR3M stations that run everything before new WXEXCEPTthat only one, WTP90. That means purchasing even the cheapest WT1 90W station for that iron alone makes absolutely no sense. I would rather hack WR3M to handle WTP90 and forget about all those WT power units.WTP90 iron is kinda desirable and beats up my current WP80 in usability. Yet anotherHUGEadvantage of WTP90 is its THM tips. WP80, even being 80W is just a kids' toy with its LT tips wrt dumb 40W iron with a regular big chunk of copper tip when it comes to solder/desolder e.g. even small thru-hole electrolytics from multi-layer PCBs.WTP90DOESheat up when connected to WR3M but display constantly toggles between temperature and all dashes and I don't know if that flashing temperature reading is not totally bogus.WTP90 supposedly has a motion sensor in its handle instead of nothing or reed switch so it would require some hardware mod in WR3M to be able to read that sensor as well as firmware hack. Nothing special, not rocket science but it would be very nice to know what motion sensor (accelerometer?) is in that handle, what ID resistor (or whatever) value is, what thermocouple/thermistor is used and how it is all connected.Any info on WTP90 handle disassembly would be also helpful -- it looks like everything is fixed permanently to the handle and those are pretty expensive to just rip apart and throw away. I do have only one here so breaking it is not an option.It would be also nice to get some dead/broken WTP90 handle if somebody have one. I would even pay a reasonable price for it.

author: ksilabs
author_rank: Regular Contributor
timestamp: April 10, 2019, 09:59:21 pm
content: OK, for all those who might be interested here is what's in that WTP90 iron.The heating cartridge has 4-pin connector. Looking at the plug (towards the tip) with a slot in that plug at the top, pins numbered CCW with pin 1 is top left, pinout is:1 -- Common Heater/PTC sensor2 -- Heater (~6 Ohm, 90W @ 24V)3 -- PTC sensor (probably Pt100, crappy multimeter shows 110 Ohm at room temperature)4 -- Tip (for grounding)Now the handle part, looking into the plug from pins side with key at the top, counting CCW, pin 1 at the left top, pin 6 (right by the key) missing, center pin is pin 7:1 -- Cartridge pin 1 (Common Heater/PTC)2 -- Cartridge pin 2 (Heater)4 -- Cartridge pin 3 (PTC)5 -- Cartridge pin 4 (Tip, for grounding)The interesting stuff is between pin 3 and pin 7, not connected to anything in the cartridge, handle only. It is 2 kOhm resistor (seems to be Weller's ID for 90..100W or so) when handle is stationary. When handle moves this connection breaks momentarily so pin 3-7 connection becomes open. I assume it is some pure mechanical stuff that breaks contact when moved (mercury switch or whatever.)That should be sufficient to make a DIY power station or hack any existing one to work with WTP90.There is absolutely no reason for buying those WT1/2 stations -- they do not provide anything special and all of those (except WT2M) are 24V-only so they won't work with 12V Microtools (WRMP, WRMT etc.)And as it's already been said WTP90 is theONLYmember of WTx tools -- they dropped everything else in favor of WXx stuff to rip off their customers one more time as it is not compatible with any older tools.