Category: Repair

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A journey of repair – Dynatron SRX 26

Let’s go on a journey of repair with Jeffrey. We have a Dynatron radio model SRX 26. I think it’s from the 1970s. The radio came from Henry which has been in his family since it was new. Unfortunately it has been waiting on me to repair it since September 2020.

I started off by wiping all the dust I have let fall on it. It is a crazy heavy thing. The best way to start is to have a good look over the radio. The point is to find any problems with the cable and to check it is safe before ever plugging it in. It also seems to be missing its record player cartridge (the needle).

The radio lead and fuse are the next places to check. It is using an older style of plug that should be replaced at some point. The fuse and lead are fine. Now for a power-on test. the unit is not showing any signs of life.

Now to take it apart and show everyone’s favourite part the insides. There looks to be other historical repairs carried out. If you look at the above image on the left-hand side.

An internal mains fuse looks very “crusty”. After taking it out it’s clearly blown. There are also two more fuses that are blown. The type of fuse is nicely labelled on the radio but I had none in stock. A short walk down to RS and picked up a bag of replacement fuses.

It came alive! Well it turns on anyway. The next step to try and find some suitable audio leads to test the sound. I only had a headphone adaptor but soon was getting sound from the radio but with a lot of hisses.

To overcome the hiss, I attacked all the knobs with some switch cleaner. You take off all the knobs and spray in the fluid. Give the knobs a good turn, backwards and forwards to work in the cleaner.

The last job was to mount the speaker port that was loose in the cabinet. Unfortunately without that type of lead, I could not test it. 

Check out the radio in action in the video above. The radio seems to work fine with headphones. The turntable needs a cartridge but that is a job for the radio owner. If you would like to see more photos of the repair check out our gallery.

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Casio SK-1 Repair

A story of repair by our member Jeffrey.

I do like the chance to repair things every now and again. It allows me to get away from coding and try something.

This Sunday I had a look at this broken Casio SK-1. A classic small sampling keyboard made by Casio from 1985.

https://en.wikipedia.org/wiki/Casio_SK-1

From the owner, they didn’t have a plug for it and it was no longer working with batteries and the last time they played it the sound was a bit off.

I got the unit to power up with an adjustable voltage supply but taking care of the odd centre pin negative configuration. It can certainly make noise.

Finding the service manual online, made opening it up fairly straightforward. I can see some type of liquid had stained the area around the battery compartment.
A good while cleaning contact points and spraying it with a load of compressed air it looked a lot better. Now testing with five AA batteries the unit came to life.

Now for the odd sound. It seems when the volume is about 40% and a few of the bass notes are played distortion comes to visit. Thinking it might be just the inbound speaker, a line out was plugged in and it had followed us there.


The demo mode and other instruments at higher volume seem to be free of this distortion. A visual inspection of the caps and parts on the board, I saw no immediate signs of damage.
I called it a day before reaching for the oscilloscope and began probing singles and that’s all the time on I had on a Sunday morning.  For more photos check out our gallery.

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More Appliance Repairs

We are no stranger to appliance repairs at TOG. In the past we have taken part in Repair Cafe’s, and we’ve looked at things brought to us by members and visitors. This time it was a Beko DW600 dishwasher that kept burning out its water heater relay every few months. The heater should only be on when heating the water but it seemed to be on all the time, and the machine could be heard gurgling and hissing when filling. On investigation, the Omron G5 relay that powers the water heater had failed with visible burning on the case. The relay failed in the ON state.

This is a very cheap part…. less than 1 Euro. After replacing it several times a few months apart, a bigger and better relay was found after a rummage through our electronics room. A Crydom D2450 solid state relay rated at 45 Amps and zero-crossing switching no less! This should have no trouble handling the approx 7.5A that the heater draws.

What was causing the original relay to fail is not certain. It doesn’t have much air circulation where it is mounted, and the the location of the control PCB itself is very close to the hot inner door of the dishwasher. So time will tell if the new relay can handle the job.

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Welder repair

An ancient proverb says that power tool failures occur in threes. During the same week that the lathe motor burned out and the compressor wire meltdown has turned it into a scary noise machine, we also had a mysterious malfunction in one of our welders. It didn’t release any smoke, didn’t make weird noises. It just didn’t weld. 0 volts across the output.

Inside of the welder (top view) before the repair attempt. Note that a large number of similar – but not identical – top boards can be found on Aliexpress.

This machine, a small 180A TIG/MMA inverter welder, has recently been repaired. It was not used heavily, as TOG has only so much use for welding. In fact, it was only used by a couple members to practise their welding skills.

On one hand, this machine was 5 year old, has been used extensively in the past and could have been written off as death of old age. The cost of a commercial repair would probably exceed the value of the welder. On the other hand – why not try to repair it ourselves before scrapping it?

Continue reading “Welder repair”

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Sandymount Repair Cafe – CANCELLED

repaircafebanner

Repair Cafe  returns to Sandymount on Saturday 7th of March 2:00pm – 5:00pm. The event were expert volunteers help you repair everyday items and talk you through the process. The event is totally free.

Bring along your broken items and learn how to fix them alongside expert volunteers…. anything from stereos to suitcases, lamps to laptops, chairs to chinos and plates to parasols.

TOG will be making up part of the team of volunteers on the day. The event takes place in Christchurch Hall, Sandymount.

-Update- This is now cancelled. https://www.facebook.com/events/804078342975111/