HP AC Power Adapter 0957-2242 repair

Had a broken HP-Photosmart printer power supply. Its parameters are input 100-240VAC 50/60Hz and output 32VDC 625mA. Condition  - not working. My first steps were measuring output voltage on DC cable on pins 1 and 2. No output. Green LED is not on also. Checked AC cable for continuity. AC cable was OK too.

Next steps apparently was to suspect inside electronics. I started to open supply enclosure hoping on easy fix. You need to unscrew hex bolt from bottom. Enclosure is holding on some clips what I did not know at that moment and made unnecessary damage to plastics. Later had to use an epoxy glue when assembling back.

Shortly problem were short diodes (1N4007) in diode bridge, which led to burnt fuse. It can easily be checked with multimeter in resistance/diode mode. Diodes were in short, and fuse in open.

In picture below you can see bad components.

At the moment I had no exact parts available, so I replaced 1N4007 with 1N5408 and fuse with round one (same rating F4A) with piece of wire soldered to one of outputs to reach holes in PCB.

Here is how board looks with replaced alternative components.

Power supply is functional again. Hard to say to what was the main reason for broken diodes. Maybe some voltage or current spike while turning on...

Digital DVB-T tuner ETR-500CHD repair

Symptoms were following - after turning on tuner shows "Initializing..." on grey background on TV screen. After a moment screen goes black and no picture anymore. Next idea after checking power supply output voltages inside of device was trying to update firmware. Unfortunately that is quite an old model and I was not able to find an firmware file. But I was lucky trying contacting support at https://www.elpa.lt/ I described the problem and after requesting serial number of my tuner they sent me "dh-update.ud" file. Flash needs to be formatted (I chose FAT16 to be sure), copied update file to it. And than with USB Flash drive connected turned on the tuner. And magic happened, LED indicator started to blink indicated different update stages. It took maybe 3 minutes and now tuner is alive again.

Repair of a remote

Recently my sibling gave me DVB-T set top box describing problem - probably remote is bad. Receiver itself was functioning OK, using face panel buttons, so I decided to start investigate remote.

Checked batteries -> OK, looked on IR led through phone camera kind of blinking but little bit strange. Checked  remote internals visually, kind of OK. Resonator looked little bit suspicious, it was not fixed to PCB, but still connected and soldered well. I have seen lot of times badly looking resonators but I have never needed to replace one. Thought this is probably same also this time. After checking everything all is in place, remote still not working. At this moment one could just give a try and replace resonator, but I wanted to make sure. I have no scope available, but than I remembered I have multi-meter with frequency measurement option. I measured resonator outputs while pressing remote key. And noticed strange behavior, frequency value started with 98 KHz, and than fluctuated up to 1MHz and again down below even those 98 KHz. It does not look normal for resonator which should be running around 455 KHz according to figures on component package. Originally there was green rectangular component, letters PG on top and NSB 455J. Not clear is it a manufacturer's quality issue or result of badly dropped remote. Anyway I was lucky that I had a spare part in my component storage, replaced and that was it. Remote is functional again.

TomTom Start 20 trouble

I am a lucky owner of navigation system TomTom Start 20. It works quite good, must say and I am satisfied in general. After a while of using decide to update maps and software as this is included as a lifetime service.

And than I got in 3 hour fight to connect the device to PC. I reinstalled software, installed/reinstalled drivers. Tested on 2 computers with 4 different USB cables. No luck. And than by accident saw a message on navigator screen that I must use original cable when connecting to computer because other cables might not work. And yes, found an original cable connected and it magically started to work.

Don't know yet how this TomTom cable is different (maybe data lines swapped ?), but lesson here is to read messages and manuals which are provided by manufacturer. Sometimes it can save you a lot of time. ☺️

Office Professional 2003 installation

One day there was need to reinstall old home laptop. It is still working acceptable, and I also decided to put into it a new SSD drive. So why not reinstalling? But story is not about that actually. I have official Office 2003 version bought for that particular device. But unfortunately held into closet for 8 years CD-ROM was not able to start installation because of corrupted files. Visually there was no any indications that CD-ROM is bad but still it was not working on any of several computers.
Contacted Microsoft support. They politely told me that that version is not supported anymore. Actually it was not easy to find an official original installation ISO file. I spent a good amount of time. But luckily I ended at this site.
I downloaded needed ISO. Installed. Activated. So far works OK. Good.