Help repairing Aim-TTi TSX3510 - Page 1
Forum section: electronics / repair

author: Thcauhy
author_rank: Newbie
timestamp: November 18, 2024, 03:18:31 pm
content: Hello everyone, my TSX3510 failed recently and i want to try repairing it.It failed while i was charging a 12V lead acid battery, i heard a loud arc and saw a bit of flashing inside the unit and my apartment breaker(16A-250VAC) popped.I tore it down and found the damage shown in the photo.I don't know if there were traces there or something(like a piece of conductor) fell thtough the vent holes of the PSU shorting something.I found the manual in another thread but it seems that is for an old revision, parts like D33-D34 or L7 aren't present on the schematics.How can i know if there were traces there?The PSU fuse is still good and i tested components around the area(bridge rectifier and capacitors) and they seem to be good.I didn't try to turn on the unit after the incident happened.What would you guys do? I can't find photos of this revision and check if there should be a trace where the pcb is burned.All the help is appreciated, thanks!

author: nctnico
author_rank: Super Contributor
timestamp: November 18, 2024, 04:02:55 pm
content: That is a nice one!My guess is that it is dust / moisture related with the inductor having a wire sticking out to close to the resistor or trace. I have had a similar incident with an oscilloscope I didn't let warm up long enough after it got delivered. A wire from an inductor was too close to the chassis and together with moisture, it arced over and caused the RCD to kick in.

author: Thcauhy
author_rank: Newbie
timestamp: November 18, 2024, 04:44:23 pm
content: Thank you for your reply, you think i could try powering it on like this?Reading through the forum i heard about placing an incandescent light bulb in series to limit the current if something shorts again, should i try that?

author: macboy
author_rank: Super Contributor
timestamp: November 19, 2024, 11:31:43 pm
content: I had a TSX1820 (almost the same) fail with similar symptoms. Arcing sound followed by blown fuse. In mine it turned out that one of the large electrolytic capacitors after the mains rectifier had shorted out internally. If you don't yet have the service manual, I had posted it on the forum in the past.

author: Thcauhy
author_rank: Newbie
timestamp: November 20, 2024, 08:47:51 am
content: Thanks for the reply!Yes, I found the manual you shared but it doesn't have the last schematic revision apparently, i can't find on the schematics components like the big inductor L7, L6, diodes (D33 and D34, see the first photo) and a mosfet that are on the heatsink right over the burned marks. I think it's a PFC circuit (or i don't know, someone can correct me on that) added in the most recent version.I asked Aim-TTi for a service manual and they sent me the same manual you have, so no luck there too.I forgot to mention that i'm measuring 85 ohms between ac inputs, so i probably can't power it up.

author: Thcauhy
author_rank: Newbie
timestamp: February 03, 2025, 06:46:21 am
content: Hello guys, didn't have much time before so now i'm back trying to get this psu to work again.I finally tried to power up the unit with a 150w halogen lamp and the bulb flashed at the beginning but after 3-4 seconds it shuts down and the unit powers up. tried to load a bit the psu in this state and the output seems to work without a problem (put a 1ohm resistor and got it to 3-4volts, after that the voltage drop on the bulb becomes too high and the psu shuts down).Testing like this the voltage at the socket is around 220V.Checked with a termal camera the start up, with the bulb flashing, and the units powers on when a SL15 1006 NTC inrush current limiter gets around 40-45°C so i guessed that was normal behaviour.I thought the next step was powering it directly from the socket without the current limiting lamp in series and...BOOM! The current limiting thermistor exploded :'(The NTC now measures around 20ohm at 20°C and a piece of it is missingThe unit with the lamp in series seemed to work fine, could the NTC be the only problem?At this point i think that the failure i had while charging the battery was a foreign object that fell through one of the venting aperture of the chassis.What do you guys think? Is it possible that some other components are failing?Thanks again for all the help!

author: Thcauhy
author_rank: Newbie
timestamp: April 12, 2025, 07:47:06 pm
content: Just an update, I replaced the NTC and the PSU is working like a charm.Thanks for the help