PACE ThermoJet TJ-70 Issue - Page 1
Forum section: electronics / general

author: timbocgn
author_rank: Contributor
timestamp: July 03, 2023, 07:58:34 pm
content: Hi PACE experts,I have upgraded my MBT 250 just lately with a used TJ-70 handpiece. Unfortunately it is not working as expected.- I powered it up to 482°C (900°F), temperature reading on the station is correct- I have used a curved single jet tip- By no means the hot air is able to melt any solder - it is too cold. I measured it to be about 220°CI checked the following:- I measured the handpiece temperature without tip and it is following the temperature on the station (max about 500°C)- I tested the sensor and heater resistance, which is 6 Ohms and 120 Ohms and according to spec- I checked all the cabling in the handpice and also the airflow without tip - which is okay and hot (around 330°C)Any idea? Can it be the tip? Or anyway the heater assembly?Thanks in advance,Tim.

author: asis
author_rank: Frequent Contributor
timestamp: July 04, 2023, 10:12:53 am
content: Hi,I did it easier.I bought a Chinese pump and built it into the PRC2K case, using the "Pulse Heat" channel with a triac, connected it to a separate step-down transformer and got adjustable airflow.The MBT/PRC pump is too noisy.It is good for desoldering pump.

author: timbocgn
author_rank: Contributor
timestamp: July 04, 2023, 07:29:52 pm
content: Hi guys,my vacuum / pressure gauge (super cheap car stuff) just arrived. And...vacuum super according to spec, but no pressure on the output air port.Taking everything apart....removed the internal VisiFilter stuff directly connecting to the pump...way more than 1 bar of pressure (spec is 0.48 bar). Connecting everything just without the VisiFilter...0.45 bar at the output air port.Heating the TJ-70 up...and solder is melting like a charm.Problem solved.Cheers,Tim.

author: GLouie
author_rank: Regular Contributor
timestamp: July 08, 2023, 04:49:57 am
content: So the internal Visifilter was clogged? And vacuum performance was fine? That is a bit odd, assuming you use an external Visifilter on the vacuum line.I recently had my MBT250 pump connecting rod break. I can also see how the rubber sheet pump mechanism could eventually deteriorate - mine seemed fine after nearly 30 years. There is another thread here showing the pump.

author: Arhigos
author_rank: Regular Contributor
timestamp: July 09, 2023, 02:51:13 am
content: Hi. I have Both MBT-250, MBT-350 and ADS200 and all accesories. Seems like TJ70 belongs to Intelliheat system (which is MBT350) while you have SensaTemp system (which is MBT250).They are not interchangeable even thought it's a same connector. For example when I swapped tips between ADS200 and MBT350 i burned tip on one station and another station had a very cold tip.I will attach a picture of my old MBT250 system with thermojetNeverminnd i just found that you got everything working

author: timbocgn
author_rank: Contributor
timestamp: July 09, 2023, 01:45:26 pm
content: Yes exactly and easy to explain. The visi filter was not clogged but leaky.When using the vacuum this did not hurt, since it is on the pressure side of the pump and the air could stream around.When using the air pressure, the system could not build the relevant pressure since the air left the system through the filter.

author: timbocgn
author_rank: Contributor
timestamp: July 09, 2023, 01:48:19 pm
content: You can get the TJ in two different configurations, mine is for SensaTemp, which is the old system. Mine is from May 1995.In case of the TJ it is only a different wiring of the connector (as far as I understood), you get one one heater replacement type.

author: GLouie
author_rank: Regular Contributor
timestamp: July 10, 2023, 02:14:00 pm
content: On my MBT250, the internal Visifilter appeared to be a different item than the external Visifilter with replaceable filter. I was intent on fixing my connecting rod and my internal Visifilter seemed fine, so I ignored replacing the filter when I bought parts.I do not know if the filters are interchangeable, you might post the answer if you replace your internal filter.Quote from: timbocgn on July 09, 2023, 01:45:26 pm

author: timbocgn
author_rank: Contributor
timestamp: July 10, 2023, 05:21:34 pm
content: No I just got rid of it

author: Shock
author_rank: Super Contributor
timestamp: July 11, 2023, 03:24:03 am
content: Remember you can only have one tool/line connected to the airflow ports. Not sure how this works on every station but I'd turn up the air to max on both ports and just adjust the one that needs it.From what I last read you only need one visifilter, the older stations had them internally. This prevents dross/flux being sucked into the pump over time when vacuum desoldering, otherwise the trap filter in the vacuuming desoldering handpiece does most of the heavy lifting.I've noticed in general filters performance tend to decrease when they are old and exposed to air humidity and heat.

author: GLouie
author_rank: Regular Contributor
timestamp: July 11, 2023, 03:45:22 am
content: My MBT250 is definitely older (1996), and has an internal, permanent visifilter just before the one air outlet, which has a mechanical valve for controlling ouput pressure. Users are advised to use the external visifilter (with replaceable paper media) in front of the vacuum inlet. I am guessing Pace figured the internal was a little extra cleanliness for the air output, and isn't really needed if you use a filter at the inlet as directed. If you don't have an external filter at the inlet, you definitely pass the gunk through the pump.What I don't understand is why they made a different permanent filter for inside; why not just use the same filter they provide for use on the inlet?

author: tooki
author_rank: Super Contributor
timestamp: July 19, 2023, 03:09:02 pm
content: Quote from: Arhigos on July 09, 2023, 02:51:13 amNot really correct. Almost all (maybe even all) SensaTemp handpieces also exist as IntelliHeat versions.The TJ-70 definitely exists for both systems.Quote from: Arhigos on July 09, 2023, 02:51:13 amThey are NOT the same connector!!!While they are all plastic-bayonet DIN connectors, AccuDrive uses the 4-pin, SensaTemp is 6-pin, and IntelliHeat is 8-pin.IntelliHeat basically combines SensaTemp signals and the signals for their older cartridge heater system, HeatWise, onto a single connector. That’s why you can get an adapter to use SensaTemp handpieces on IntelliHeat stations.