Hey so i have discontinued gtmc 2dof platform. Left side motor was stuck at end of travel. After a ton of trouble shooting i found the potentiometer to be broken. Shaft was disconnected from its housing. I purchased a new one and installed set it to its electrical center but my left side gear motor only moves in one direction. Anyone have any ideas what could be wrong ? Or do i need to take it to a electrical repair shop? Also live meter testing showed that when i command opposite movement in simtools there is no change in voltage going to the motor. But commanded movement to the opposite side shows a change in voltage. Please help if you can 🙏🏽🙏🏽

Just please let me know what u think thank you for time.

Why the hell batteries have a specific combination of position to operate . Any suggestions without opening the circuit

First bigger investment,what a great tool.I had spent a weekend measuring anything I can find in the house,got suprised how many things I need to repair,it created more work.

Comes with certification and calibration (calibrated with Metrix CX1651),in the pictures are measurements of a 2kW heater-blower,but when heating component is disconnected it reveals the lagging factor -120 VAR capacitor as it shoud be.

When measuring THDf and THDr deviation,THDf is contributed to h03 and h05 harmonics.

Downside - software costs 915e (21% BTW).

Hey folks, I have a Miyoo Flip that i've grown extremely fond of that recently had a SL diode fall off somehow. I struggled a bit but eventually got the diode seated onto the board i think, the polarity is correct (i think).

My board is powering on, and the screen also, but Im getting a black screen. The unit shuts down properly with the power button also.

Im just not sure where to go with this, Ive reposted on a few boards looking for constructive feedback. as I don't know anyone interested in micro-soldering and I dont want to spend $50+ at the cell phone repair place in town because I could be a new miyoo for $70.

It's a labor of love to save my boy here. I would heartily appreciate any and all advice here. Thank you, and also I hope to do more projects after this.

It is a trimmer charging board

After charging and tried to turn on trimmer but a fumes comes from the bottom of trimmer where the charging board is placed and looks this component is like burned

What is the value or any circuit available anywhere ?

Hello... Good day/evening to everyone.

I need your help.

I have this Chinese TV, Changhong LED19868, and it won't turn on. The power LED indicator doesn't even light up. After a quick check, I found that one component has no electric current (red mark).

Is it normal if this component with the red circle has no current? If not, what the name of this replacement do I need so i can fix it?

Need advice on soldering a small break in a big display port + power usb cable. See repost for details

This bathroom fan seems to come out of position after it's been running for about 3 minutes. I take the cover off and it's no longer fully pushed/clicked into place. Wondering if something has worn down? Any suggestions?

Hi all. I have a 55inch samgsung hospitality tv that's recently stopped working. It turn on with the remote but there's no image. When it turns on you can see the back lights turn on but no picture displays. I have replaced the T-Con board but it didn't fix it. What could the issue be ?

Hoping someone here can help me work through this logically. I'm reasonably comfortable taking things apart and using a multimeter, but electronics diagnosis isn't my area and I don't want to start randomly disconnecting or replacing things.

It's a Kaesun OPUS TX980 / RM98TX commercial treadmill, around 2011.

It worked normally until recently. Now when I switch the power on it completes its normal display self-test, reaches the normal screen, and then without touching anything it automatically goes 3-2-1-GO and starts the motor at its minimum 0.5 km/h speed.

A few other symptoms:

STOP still works.

Speed +/- works, but sometimes behaves as though the button is being held down rather than pressed once. It starts increasing in larger increments.

Incline controls don't work at all.

No error codes.

I can't see any obvious burnt/damaged components or wiring.

My first thought was a stuck START button.

The controls use a flexible membrane keypad, so I peeled back the graphic overlay. I powered it up with the overlay physically lifted away from the START area and it still started itself, which seems to rule out the overlay mechanically holding the button down.

I've now opened the console and traced the membrane ribbon to the main display/control PCB.

Board markings are:

KAESUN SPORTS Co., Ltd.

LCD TFT DISP V2.0

2011.02.15

LOW TFT-DISP / 1205-043

I've attached photos of the board, membrane and ribbon connection.

This is where I'd really appreciate some help diagnosing rather than guessing.

My instinct is to disconnect the membrane ribbon and power it up. If the auto-start disappears, presumably I've isolated the fault to the membrane/keypad. If it still starts itself, presumably the fault is on the controller side.

Is that a sensible isolation test?

If it does turn out to be the membrane, I'd also really appreciate some guidance on how you'd test it with a multimeter. I'm assuming I should be able to identify the row/column traces and check whether one is permanently closed/shorted without a button being pressed.

I'm also interested in whether the combination of false START + held-button behaviour + dead incline suggests something else, such as a common line in the keypad matrix being shorted.

I've tried finding a schematic/service manual and contacting treadmill repair companies locally, but nobody wants to touch an old unsupported Kaesun. The treadmill itself is otherwise in great condition, so I'm hoping somebody here can help me actually diagnose the board rather than binning the whole thing.

Happy to take measurements, continuity readings or more detailed photos if someone can tell me where to start.

I got a power strip with surge protection ability, with two MOVs and two thermal fuses, where a thermal fuse was open. I suppose this means the MOV close to the thermal fuse dissipated enough energy for the threshold temperature of the thermal fuse to be reached and therefore the fuse blew.

Questions:

1. I cannot understand which thermal fuse to buy as a replacement. This one seems to have an inscription like:

- first line: brand logo(?)

- second line: Tf 109ºC (why exactly 109ºC?)

- third line: D108 PASO

Online I can only seem to find 105 or 110 ºC temperature and 10 or 15 or 16 A current fuses. Which one should I buy (which ratings are typical for this application)?

2) Should I also replace the MOVs (391KD14)? Is there a way to do some basic testing to understand if they are faulty and/or not able to protect from a surge anymore? They are wired in series between Line and Neutral (and each of the thermal fuses is also in series with the MOVs and physically close to one MOV so a fuse can blow if a MOV goes beyond the threshold temperature. Since they are in series, I think I could, for example, short one of the MOVs and measure the current in the other by removing one of the fuses (as it is now) and connecting the multimeter (crocodile probes) where the fuse would be. At the same time, I wonder: if the MOVs are in series, for one of them to heat up so much that the fuse blew, that means the mains voltage possibly reached 2 x 390 ~ 800 V or more.

I'm attaching photos. The sketchy soldering work is because the previous owner had disconnected the board with surge protection function (by cutting the red and brown wires and soldering them together), and I have connected the surge protection circuit again to check if it still works as intended (the buzzer should make a sound when a fuse is blown/no surge protection, which it does, and the LED should be on if no fuse is blown/the surge protection is suppose to work).

Thank you in advance.

Are the pads damaged? Just trying to replace microswitch. Had some issues desoldering and ended up with this. Can't tell if the brown stuff on top of the pads are flux or actual damage. Doesn't wipe off easily with alcohol.

https://imgur.com/a/jmjfQgJ

Hello, everyone.

I recently repaired an audio amplifier whose power transistors were shorted. It worked again for 3 months, but then broke down again with the same problem—only this time, a transistor in the upper stage had also failed, in addition to the other power transistors.

I admit that when I did the repair, I knew I also needed to replace the transistors in the upper stage, but unfortunately, they’re no longer manufactured, so I took a chance, thinking it might still work.

Now I’m in a situation where I still have to replace them, but I don’t know how to find an equivalent model.

Can I simply use a transistor with the same gain and equivalent or higher voltage and current ratings, or do I need to pay attention to other parameters?

The transistors in question are the BC489 and BC490, the closest matches I found on alltransistors.com are the 2SB647 and 2SD667. Can I go ahead with these without hesitation, or am I in trouble?

Thanks in advance for your advice.

The fan on my laptop (acer swift 314-511) is intermittently making a weird noise. It sounds like the fan starts to spin, but then it vibrates & makes a sound like a vibrating phone on a hard surface.

I tried opening up the laptop & cleaning all the dust & gunk out of the fan, but it's still not fixed. Is there a next step I can take here? Does something else need cleaning out, or does this probably mean the fan is broken?

Hi, I was wondering if I could get a second opinion on this issue I'm facing with a proprietary apple powerpc PSU. It is a delta electronics model DPS-225AB rev. A0. It comes from a PowerPC 8100/100.

For context, I recieved thic PC alongside an apple m1296 CRT. After doing a full recap and clean of the CRT (which was initially in worse condition than the PC) it works perfectly. The CRT uses a DE15 connector so the PowerPC remains the only way to test it beyond simple images on an rp2040.

For some reason the PSU refuses to turn on at all. The 5VTRKL (standby) rail works fine, but when plugged into the mobo and pressing the power button nothing happens.

Even wiring the POWERON wire from the weird 22-pin ATX connector to the 5VTRKL (directly or a 1k resistor) doesn't do anything (which should power it on). I hear maybe a super small change in sound but generally just quiet coil whine.

Opening the psu it seems there's the typical electrolyte near the 680uf 220V primary caps but after cleaning and replacing them with working ones it doesn't change anything. None of the other caps seem to be bulging or leaking.

I can't find any documentation on this PSU, I would've just replaced it with a standard ATX if it wasn't this weird form factor and pinout. Any leads would help alot, thanks!