Tag: safety

What the listing stated:

old computer bit , powers up ( red light shines on ) but otherwise untested  , please note my other similar computer items      

EBay

My previous post Formatting the Psion II Datapack explains my thinking and reasoning behind making this purchase.

Most EPROMS made around this time in the 1980s had memory that could be formatted by using a method of exposing them to high levels of Ultraviolet light for between 10-30 minutes. The Psion Datapaks required about 30 minutes of “exposure” in one of these units to format the drive.

By high levels of light, i mean UV light around the wavelength at or close to 253.7nm. A UV light you may have in your home or in the form of a torch operates at somewhere around 395nm, a considerably safer wavelength of operation than what is needed to format these EPROMS.

This unit was purchased after I had spoken to the seller, a nice chap that specialised in old diy tools and computer peripherals, but wasn’t quite sure what this unit did or how it operated. He had stated that the red light was working, but nothing else. My concern here was that the UV light inside was broken, and these tubes i believe are known as low pressure mercury discharge tubes, and finding them in this size is pretty difficult to say the least. The UV tube in this unit could potentially be 40yrs old as this is a Mk1 unit circa 1984. I just don’t know if its tube has ever been replaced at all in its lifetime. Have a read of this post by Dave Curran who had similar issues sourcing a light supply for one of these units, it resulted in him having to make a hybrid concoction combining one of these units and a cheap Chinese import – Eprom eraser/upgrade

I asked the seller, John, if the Ultraviolet light inside was operational and I have supplied a screen shot of his reply:

When I received John’s reply I jumped in with an offer and this was accepted. He had been so helpful. I’m now awaiting the unit, but I’m now a lot more confident that the unit, and most importantly the UV light is currently operational. However it’s probably going to be subjected to some pretty rough conditions on its delivery journey, so I’ll keep my fingers crossed for now.

This formatter is a series one version that came out around the same time as Psions Mk1 organiser first appeared on the scene, circa 1984. It was used right through to when the MK2 organisers were released sometime between the years 1986/89.

This unit will be cleaned, opened up, checked for electrical and mechanical stability, its safety features will be confirmed and it will then be reassembled and PAT tested prior to use. Once this is done i will attempt my first format of a Psion Datapak whilst the unit is in my possession. However we have a little way to go just yet, before we can consider carrying out that task.
The seller was very prompt at getting the unit out to me as it has arrived less than 24hrs later.

The general condition on first inspection is that it looks good, but it’s very dirty and has a slight musky dampness to it. I have given the plug and the cable and case a good clean with a bit of degreaser and this has cleaned well. I’ve done this just so getting inside is a slightly more pleasant experience without my hands getting covered in gunk. The unit looks a lot bigger in the pictures. It only measures 19cm L, 10cm W and 7cm H, so in theory it’s relatively small.

Before I do go inside I have first checked the plug, it currently is carrying a 13amp fuse that is way to large for this unit. It only requires a 3amp fuse so I have replaced this. I haven’t used the Pat tester yet I’m just using the multimeter, and I’m a bit concerned as there is no continuity between the earth pin and the unit case. Time to get inside.

Inside looks tidy but I then become aware of a problem immediately. The earth wire from the mains cable is just sitting there in mid air connected to nothing. No wonder there was no continuity. I have now connected this back in place where it should be and I now get a good earth continuity throughput the casing. All other connections checked and tightened accordingly. This proves that the Pat test would have failed miserably. This was a potentially dangerous situation, that’s why it’s best to carry out these checks on any old powered units you get from a third party. Trust no one.

Next I need to check that the safety switch that turns off the UV light when the drawer is opened is operating. Again I use the multimeter to probe the switch and this seems to be ok. A good listen to the action confirms that it is clicking in and out. A quick clean inside and then the internal checks are complete.

There is no real way to test for actual operation until the safety case is back in place, that’s the safest way. Case on and another quick clean and the unit is looking good .

At this point I’ve carried out the Pat test before plugging it into the mains and the results have come back good and it’s a pass, the earth is good. I’m now confident about plugging the unit into the mains.

Everything seems fine I now just need to place a Datapak inside to see if the format process works. Also it’s a good time to check if the 30 minute timer is working. No time like the present, so I’ve found a suitable candidate and what better way to do the 30 minute countdown than with a Psion organiser I just happen to have hanging around. Here goes 🤞

The unit has been on about 15 minutes and all seems fine, the unit is not overheating and there is nothing occurring that shouldn’t be occurring. Fingers still tightly crossed. 🤞 The Psion timer duly sounded at the 30 minute mark, the unit turned itself off about 2 minutes later.

So 32 minutes seems to be the actual time under the lamp. Not too bad considering its age. The unit was only slightly warm to the touch after this time. I’ve left the Datapak to allow it to get to room temperature before testing it .

Here we go, and it’s fantastic news as the format has worked. When plugged in it has informed me it is going through the sizing process that occurs on these organisers when you put in a newly formatted pack.

And when you go to check the info you can see the previously stored old data has now been deleted.

I now have a very useful, safe and working item of equipment. A very slight mustiness remains but that is only to be expected with an item that is 40 years old that you have had no input into how it is stored. I’ll probably store this in a sealable bag with some silica gel sachets to try and draw that mustiness out. I’m really pleased with this project and now have a very handy piece of kit to boot.

As I said earlier, make sure you always check thoroughly any items electrical such as this, coming from a third party. It’s your life, preserve it, safety first and trust no one. It’s a good mantra in this aspect or restoration.

Another item saved from landfill 👍

Thanks for taking the time to follow this project.