Hardware Repairs

© Richard Ashbery, 2015

Introduction

Some hardware can be repaired. Devices containing switch mode power supplies (SMPS) like monitors and computers are worth looking at repairing. This article describes my experience of repairing an old Acer monitor, model AL2416W and an Iyonix - Aria power supply.

Monitor Repair

Acer monitor, model AL2416W as Supplied by Castle Technology Ltd.

My first experience is with the monitor which suddenly stopped giving a video display. I 'googled' "Repairs to Acer AL241W" and I was presented with an excellent Youtube video from an American technician who went through a detailed repair procedure. He indicated the main fault is with bad electrolytic capacitors which either significantly change their value because of loss of electrolyte or leak. So I thought this worth a try. I removed the covers and shield and was presented with three boards - a SMPS board (middle), a high voltage (HV) board (left), a video controller board (right). In my opinion this monitor is definitely worth repairing if possible - the build quality is excellent and although analogue it gives a consistent colour rendering across the whole screen compared with some digital monitors. There was no evidence of leaking capacitors but due to ageing all values are lightly to have changed some probably to the point where they are not working. Taking it in stages I decided to only replace capacitors on the SMPS and the high voltage board. The SMPS has an aluminium plate over the power semiconductors which needs (after undoing 2 screws) to be carefully prised off to gain component access. All capacitors were removed taking note of their values. All through holes on the SMPS were cleaned to make way for the new components. Capacitors on the HV board are quiet easy to remove as they are surface mount.

Using my supplier of choice, Farnell I ordered all capacitors and fitted them. After reconnecting the boards and replacing covers I switched on and the monitor burst into life. I now have a working monitor thanks to the excellent American video tutorial. So far I have not had to replace the capacitors on the video controller - these may be more difficult because of the multi-layer nature of the PCB.

Iyonix - Aria SMPS Repair

Antec AR350 SMPS Used in Iyonix - Aria

Now for a real challenge - repair of an Iyonix (Aria) Antec AR350 SMPS. I wonder how many RISC OS users purchased the Iyonix - Aria. I did and haven't regretted it. It's been working reliably for years until an intermittent issue where the GUI wouldn't display on re-boots. Each time this happened I had to power-down the Aria, leave for 3 minutes and power-up again. I replaced the power supply at significant cost and although things improved slightly it didn't get rid of the problem. Knowing that electrolytic capacitors have a limited operating and storage life power supply problems can sometimes be cured by replacing them.

I took the covers off and looked in horror at its complexity mainly due to numerous surface mount components and the closeness of the tracks on the main PCB. I thought this is too challenging so I boxed it up again. I recently decided to have another look to see if it was possible to replace them. Essentially the SMPS was in good condition with no evidence of burnt components and providing I didn't need to reboot the Aria worked happily all day.

Criteria for Capacitor Replacement

Simply this - if I could remove all 14 capacitors leaving nice clear holes in the PCB ready to accept new ones then it might be worth the effort. There were two problems I was confronted with...

1. The aluminium cooling fins needed bending back in two areas in order to get access to some capacitors.

2. Capacitors are fixed in position with a tough cement which is quite difficult to remove.

I was able to prise the offending cooling fins upwards to give access and the cement was broken by gently rocking capacitors back and forth.

I ordered 14 new capacitor and fitted them. Care has to be taken in selecting ones that will fit - many are either too tall or have too large a diameter. The single high voltage capacitor had to be sourced from RS Components because the Farnell ones were too tall. I ordered capacitors with a minimum 2000 hours at 105 degrees manufactured by Panasonic or Rubicon.

Fitting replacement capacitors

Only attempt this job if you have experience of working on board level repairs. Inspect the PCB carefully. Any signs of burning or burnt components indicate that semi-conductors have probably been destroyed. Cut your losses and buy a new supply.

The following points need to be considered when doing this task:

Finally

On replacing 14 capacitors in the AR350, replacing it in the Aria and switching on, the computer booted into the desktop - sigh of relief!!!! Re-boots seem to be OK. However I still have an issue where the computer doesn't boot/power-up after being off overnight and a reset is required.

Repairs cost in the region of 30-40UKP bearing in mind there is a minimum charge/order of 20UKP excluding VAT when purchasing from Farnell and/or RS. I prefer Farnell because of their attention to quality. However both sites have excellent websites with extensive technical product information.

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