Hi,

It's been a while since I've posted in the community, so I hope you won't mind me coming back for a tech-support question.

I've got an Izzo Alex MKII, and this morning it gave up the ghost. I came downstairs to find it partially heated up (around 0.5 bar) but with both red+green lights off and unresponsive (i.e. no power to heating element or pump). The Gicar controller seemed rather hot, and had that "hot/burning electrical" smell. It had clearly been subject to heat as the once silver sticker has been progressively getting more and more brown over the past 2.5 years of ownership. When I opened up the Gicar box, the large orange transformer was hot to the touch.

How likely do you think it is that this is the point of failure? Can anyone familiar with the wiring in this unit suggest some useful places to check voltage / resistance to help diagnose the problem?

I have been in touch with a service contact Chris Coffee, who fortunately has a replacement part in stock -- he has been quite kind in even considering my technical problem in my connection to them is via a second-hand purchase. I'd like to try to exhaust the other possibilities, however, before investing in a substantial repair cost.

Help me, Home-Barista.com -- you're my only hope!

A quick self-follow-up: I believe that I have isolated the problem to the transformer in question. When the Gicar controller is disconnected (but the component is still on the PCB), the transformer shows infinite resistance on the primary windings. In-circuit, there is 120VAC across the primary windings while the secondary windings are at 0V.

My search for a replacement part (Myrra 44135) has so far been fruitless -- none of the usual distributors I use (digikey, Newark, Future Electronics) seem to carry it. Has anyone ever successfully sourced one of these?

If you can find out what the secondary voltage is, you could find a replacement easily enough, though you need to be mindful of the heat rating and current.

But that is no guarantee that something else didn't blow, causing excessive current consumption and burning out the secondary winding.

If you're adventurous, you could try a (fused!) variac as a stand-in to see if the rest of it works.

Thanks for the reply, Allon.

I'm hoping that everything else on the machine is OK -- the secondary coil is intact (measure 26 ohms resistance out of circuit -- neither open circuit or short), whereas the primary is an open circuit.

I know that I could replace with an equivalent component, but my concern was finding something that will match the PCB mount of the original one (i.e. so that it installs back into the controller box cleanly). Unfortunately, I don't have a variac to test with.

Myrra 44135 is:
2va, 12V 167mA ouptut, (20.7 no-load voltage), 70C ambient

(source: http://www.myrra.com/products/4400SERIE...55-117.jpg)

Newark is their distributor in the Americas. You might try giving their sales rep a call.
They do have the 230V version......

(it is a non-stock part, so it will need to be special ordered)

I use either Farnell now element14 OR Radio Spares.. Both of these places have pics / technical info and lots to choose from.

The Transformer is a common fail point in most Control units and usually 9 or 12 on the secondary and replacements can be had with a higher Amp rating.

The trick it to be exact as to size...

The secondary pin-outs can be the lynch pin but with two units I had here, where a direct replacement was not available, a little smart wiring and cross linking had bot up and running.

Let us know how you go.

Thanks again, to both Allon and AngerManagement.

I have contacted Newark, my usual supplier for electronic components (which is the same company as Farnell/Element14, but in Canada [and USA, I think]); while they don't stock the particular part, they're willing to special order from Myrra if the part is still being actively made. I am waiting to hear from Myrra on this issue.

I have taken a look through the Newark catalog and they do carry #44123, which is the identical part but for 230V mains (as Allon said). Hopefully it will be easy enough for them to source the 115/120V part.

That is the one I have ordered a few times 44123

Remember many ways to skin a cat

Don't forget to look at other options.. Like

BLOCK - AVB2.3/2/12 - TRANSFORMER, 2.3VA, 2 X 12V

Thanks for pointing me to Block as a manufacturer, although the extra 2mm in height (~29mm) seems to be a deal-breaker, as the ~27mm height Myrra transformer currently maxes out the fit in the case. I suppose the extra height is because it's rated at 2.3VA vs 2VA for the original -- I guess the wire gauge in the windings gets bigger for higher current rating.

I hadn't considered using a transformer with dual windings because the pinout is different. Is it acceptable to parallel the input/output windings?

The other one that I have found is from Zettler Magnetics, whose BV301S12020 seems to be a drop-in substitution. The pinout/profile of most of these PCB transformers appears to be very close (standardized?), so I'll keep looking.

EDIT: I think I found another one -- does this look right to you?
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=553-1630-5-ND

If ya make assumptions or not fully across many things, any thing electronic can either WORK Go BANG OR Kill you.

See here http://ww2.pulseeng.com/products/datash...007_09.pdf

Then look at pic 2 and pic 4

Pic 2 is the 240 In across 1 and 5 with TWO lots of 12 out..

Pic 4 is 115 In on 1 and 2 and 4 and 5... with TWO lots of 12 out..

So to run a pic 4 config as a pic two, you would need to link pins 2 and 4. And this would in effect make a pic 2 with a 230V input

To make it a stable 115 InPut, you could either just connect either 1 and 2 OR 2 and 4 to your supply... However the holes in teh cct board may not allow this and the unused terminals should also be insulated . Thus you could run some links to connect to the actual holes in use...

The best way would be to parallel up the input. That is link 1 and 4 and 2 and 5 So that you still have only 115 coming in but your sharing the load on the input windings etc.

Either way, it will need some fine work and any wiring will need to be at teh correct insulating rating rating as you do not want it to break down or it will be dangerous. Like it or not, get a qualified person to do and test before putting together and trying to run the machine.. Other wise a risk of BANG or DEAD and neither is acceptable.

Now if ya was in Brisbane, Australia ... A couple of minutes and your done and ducted

If ya never post again, we know what happened.. SO post again