HP Instant Ink referral code - free month of ink!

Just a quick post about HP Instant Ink.

If you've bought an HP Printer and are contemplating signing up for HP Instant Ink, click though to HP using the link below and we'll both a get a month of free ink. 

http://try.hpinstantink.com/vNgGQ

If you are already on the HP website it may ask you to enter any codes that you have. The code to use (amongst any others you may have collected) is vNgGQ

More soon, no doubt....

D

Ideal Mini C24 - fan replacement

So, we're in the Chinese Virus lock-down and I was thinking that it was about time I replaced the fan in my boiler. The current fan is on its last legs - the bearings are shot and the fan is noisy and keeps seizing. When this happens the boiler won't fire at all (so no heating or hot water). I've been able to effect a temporary repair each time by opening up the boiler and squirting some WD40 on the bearings. The repair lasts a few weeks or a month or so, and then the fan seizes again. Last week I found a "nearly new" fan for sale on Ebay so I bought it - £40 delivered. Today I fitted the new fan and this is how.

This is the boiler. I sprayed the panels black a couple of years ago. Note the wooden panel underneath. I made this to cover up the abominable pipework underneath...

What on earth were they thinking?

Anyway, here are the required tools. The thing at the top is the longest cross-head screwdriver I could find. I also used a flat-head screwdriver, as will become apparent in a moment.

Right, the outer panels are now off. The power supply to the boiler is also off! Next step is to open - slightly - the tabs holding the inner panel in place. There are three tabs on each side.

Next, undo the four screws on the front of the inner panel...

... and the screw on each side of the inner panel. The inner panel should pull forward and away.

This is what's behind the inner panel. The five screws in this picture will need removing in a moment. Before that, some fettling in the fan area is required. The fan is in the top right-hand corner of the picture.

First, undo the two screws holding the fan/flue together. With the screws removed, completely remove the front bracket. Note that the screws go into captive nuts on the back of the bracket. Still, it is worth putting a bit of tape over the nuts just in case they are no longer captive...

Thus...

Disconnect the electrical connections to the fan (including the earth wire on the side.

Pull the wire and grommet away from the fan shroud. Also, there are also two soft hoses attached to the fan body which should be disconnected. Make a note of which hose goes where.

Now undo the five screws on the front of the inner panel and remove the panel. Be very careful with the panel - it is lined with fireproof material which I imagine would shatter if the panel was dropped or flexed.

This is what the boiler looks like with the front inner panel removed. It might be possible to remove the fan from its shroud at this point. It is held in place by three small screws accessed from underneath. To be honest, I couldn't be bothered even trying and instead removed the fan and its shroud in one go.

The three pictures above show the location of the fan shroud screws. The screw in the picture immediately above requires use of the long screwdriver. Once removed, very carefully slide the fan and shroud forward, checking that no pipes or cables are tangled up in it. Expect the plastic join between the fan and the flue to come away at this point.

Fan and shroud removed.

This is underneath the shroud. The three screws holding the fan in place can be seen. Remove the screws and the fan comes away.

The pictures above compare the old and new fans. Note the date code on the old fan. And the new fan was made a couple of years ago, it seems. The part number says it is for the C28 or S28. However, it is identical to my old fan and is minty mint. I believe the ebay seller who advertised the fan as having only three-day's use. It also came with a new seal for the flue bracket so I used that rather than buying a new one.

New fan attached to the shroud.


Re-assembly is reverse of removable but with the following notes:

When sliding the fan shroud back into place, take care not to pinch any hoses or electrical cables. Also, it is unlikely that the fan will properly line up with the flue bracket at this stage. This is because the fan shroud is propped up by the front inner panel which isn't fitted yet. So, once the shroud is in roughly place, refit the front inner panel and only then final-fit the fan. 

This is the flue bracket back in place. 

Power and pipes reconnected. But also note the close-up of the spongy seal that goes between the inner panel and the rest of the case. "Ideal" recommend replacing the seal when the front panel has been removed. However, I replaced this seal recently so it is still nice and spongy. The original seal was hard and crispy and I had no confidence in it (not that I think a problem with this seal will cause any issues other than the boiler not igniting due to lack of vacuum in the combustion area).

Once the inner panel is reattached and screwed on, gently tap the side tabs back into place to ensure a snug fit (three tabs on each side). Then, with power back on, I tried the hot tap. Boiler fired up first time and is so quiet - no rumble from dodgy fan bearings!

I then conducted some safety tests with my carbon monoxide detector. With the doors and windows closed, no detectable CO after 30 minutes of running. This can be compared with when I'm using the wok burner on my gas hob - with doors and windows closed and the hob extractor off, the detector reports trace amounts of CO in minutes (but never high enough to set the alarm off).  I will conduct further tests just to be sure but I am happy that the boiler is safely operational. Incidentally, my CO detector lives on the wall next to the boiler.


More soon, no doubt...


D

Kenwood KA-4040R - faulty channel (fixed)

Almost exactly 10 years ago I picked up this Kenwood KA-4040R Amplifier.

I'd put a "Wanted" ad on our local Freecycle page - I fancied a go at fixing a broken amplifier - so I specifically asked for something that was broken. So, this amp was given to me along with the CD player and Tuner (all separates). The fault on the amp was that one channel was not working. At this stage I knew nothing at all about how amps work (and pretty much still don't), but I set to work with the only relevant tools that I had - a multi-meter and an ESR meter for checking capacitors. Within a short while I had found what I thought was a dead capacitor. Having de-soldered it and checked it again, it seemed to be fine. So I reinstalled it and the amp worked! Easy fix, and the amp ran fine for the next ten years, right up until a couple of weeks ago. The left channel started playing up again. This coincided with a lot of scratchy interference when adjusting the volume, and a quiet "thudding" sound on the left channel. This thudding was louder on certain inputs (CD, Tuner, Aux, Phono), but not really noticeable on the second tape input. As I was mulling this over something in the amp went "pop". I unplugged it all and removed the cover. This is what I saw:

This is a 3300uf 6.3v capacitor on the "EQ" board which has spilled its guts into the amp.

I bought a couple of replacements and fitted them but I was not hopeful that this, and cleaning up all the cap juice, would sort the issue.

I was right - with the new caps fitted there was clearly some sort of current leak as there was a very rapid thudding on all inputs and within about 30 seconds of switch-on the speaker protection relay fired. On a positive note, the left channel did now have audio, albeit quiet and drowned out by the thudding. I did some more checks. I found that about half of the diodes which appear to serve the input connections had fried. So I replaced them, along with some transistors that I'd had a hunch about.

The original diodes are no longer available but the consensus on the internet was that IN4148 diodes would serve as a suitable replacement. I managed to find some new-old stock transistors so replaced like-for-like.

And whilst I had it in bits, I took the front panel apart and cleaned all the pots with some Super 10.

So, 28 diodes (I replaced them all...) and four transistors later, and a liberal dose of switch cleaner, I now have a fully functioning amplifier again. Cost - less than £10 to fix. I am extremely pleased ;) But I am now toying with replacing all the caps in the amp - they are 27 years old and are unlikely to be in the best of shape. I like the amp and it would be a shame if it got wrecked by a failing cap.


More soon, no doubt...


D.