PAT Test - Seaward PrimeTest 100 Not Turning On - Can I fix it?

[@Mymatevince]

Great video Craig 👍👍

[@GoodwinsPlace]

Thanks Vince. It's still working which is great, but would love to know what the temporary hairdryer fix was actually resolving even for a short period.

[@davechisholm9670]

I found your video as I was looking for anyone else's description of attempts to repair a faulty Seaward PAT tester of this form factor - there are a number of different models, which look similar externally but with wildly different PCB designs inside - and no-one anywhere has found a schematic in the wild to assist - roll on the Right to Repair movement! I'm an experienced electronics engineer, and your video is a couple of years old but I have a couple of observations for you - Even with your inexperience at this point you're doing a good job with your soldering, much better than the cack-handed efforts of whoever was let loose on it before you got it! Keep learning - you can only get better at repair with increasing knowledge! I'd say this machine had been wet/damp/water-splashed in the past, the moisture leading to the dulling of the solder contacts and creating possible leakage between pins of ICs through corrosion or impurities of damp grime deposited - leading to erratic display behaviour and erratic microcontroller behaviour. It's sadly not unusual for on-site test tools like this that are in fact not waterproof (even though they look ruggedised), to be tossed in a ratty old gear bag in a van, as opposed to being kept dry on the workbench. So your decision to apply flux and reflow dull solder was a good one. It's best to use solderwick to remove as much of the old oxidised old solder as possible, apply new solder, and scrub up with IPA as you did. The two pins they soldered the battery wires onto, were the remains of a 2-pin plastic socket similar to the others on the board - I'm guessing that the previous "repairer" either wrenched the wire/s out of the crimped plug while trying to dismantle the machine, or wrenched the socket plastic off the board still attached to the plug, leaving the pins behind... and/or there was corrosion in the plug (that dull solder on that via suggests this) which ruined it, so they just soldered the wires direct to the remaining pins rather than replacing the socket and recrimping a new plug. In that case, they should have first removed the pins as you did, as the pins' actual plated surfaces may have become oxidised and made a bad solder contact. Oh and those red items are the relays you can hear clicking when it performs the tests - needed to disconnect and reconnect the pins on the IEC and 3-pin sockets in different combinations to check for crossed wiring and to momentarily connect the high voltage generator to the socket pins during insulation testing. Cheers, from New Zealand!

[@GoodwinsPlace]

Cheers for the comment, as you say an old video. I'm flying through hdmi repairs and other much more technical items these days - I should get some updated on KZbin. This machine works still but has some strange behaviour, I need to send it off for calibration but I'll need to spend a bit more time on it first to make sure it's still functioning as intended.

[@paulstimpson8977]

In the same boat cannot find a schematic online for this model, mine has a RIso fault which I think is quite common. I cannot find anything wrong but I appear to have a short somewhere, It is not on any components though so I am worried it might be in the PCB somewhere. Tried the voltage injection method but nothing gets hot and I think that is because the path might be a high current one and so not heating up. I don't have a working one to compare as this does have different voltage references Analogue Ground and Digital Ground so it might be correct. All components seem to be good so I am at a loss what do do next. I have ordered some of the IC's for this and will swap them out to see if the fault clears. The yellow capacitor in the bottom left area of the board the far right one of the four, its positive is shorted to the 2nd mosfets (between the large mosfet and the transistor) middle pin which is connected to ground.

[@steve36207]

Thats awesome craig buddy. You need to get a store open for fixes bud. The pat tester will be a great addition to the tools 😄

[@GoodwinsPlace]

Thanks but happy with just learning on my own things. Less pressure if it goes wrong. Cheers for watching, it's a different kind of fix but something I enjoyed doing.

[@kenwilliams563]

Thanks for the peek inside of one of those, what on earth is their to calibrate? I cannot see anything to adjust, so is calibration just a pointless exercise, and all it is really is a test of the instrument? Some really stupid PAT test rules, such as putting a 3 Amp fuse in a portable radio for example, when even a 1 amp fuse is more than it should be... Ken.