Leaky head?, Low flow rate?, read on…

Most of mid to low end espresso machines share pretty much the same pump and block assembly with very few differences, there are in fact just a few major designs out there most of which are aluminum/brass based and manufactured in China, however that doesn’t neccesarily make them bad.

In all inexpensive units (and some expensive units sold as “professional” but they’re actually a product of marketing bullcrap) the group head has a spring valve that opens when enough pressure builds on the head, this happens when the pump is turned on and it’s there to prevent water leakage. Some better units will use solenoid valves instead, which also allow to set the flow rate in some cases.

The passive valves used on inexpensive units require a clean surface to sit on, much like an engine valve does. The reason espresso heads can leak is simply because of an uneven mating surface (dirty valve seat or dirty valve) it doesn’t have to be a faulty part so if your machine leaks, don’t assume you’ll need rare / expensive spare parts to fix it. If you’ve taken good care of your unit chances are it needs a slight clean up and polish.

Like I said, this gparticular uide is mostly for inexpensive machines, I don’t have experience with high-end units as I’ve never had the pleasure to work with them.

Alright, bring it on!

To proceed, remove the water reservoir, portafilter and any loose parts such as filters, trays, etc. Tip the unit over, I use bubblewrap on the countertop to prevent scratches. In my case I had to remove the bottom cover (plated steel) which was held in place with 4 security torx screws.

Identify the type of head/block assembly, mine has a 12MM nut which holds the diffuser and forms part of the valve assembly itself. Other heads may use a notched nut or similar assembly allowing for a flat-head screwdriver to be used. Go ahead and remove it.

A view into the brew head before cleaning it, you can clearly see it’s become obstructred. The valve was in even worse shape!

The valve is often spring loaded and has a silicone seal / head. This is where some of the sediment build-up occurs and prevents it from sealing the boiler properly. But most of the build-up occurs on the valve body, which is often (but not always) brass, on more expensive units you may also find stainless steel parts.

Once you’ve removed the nut pull out the spring if it didn’t come out on it’s own, now that the entire valve assembly has been taken apart, use a flashlight to look into the valve body, you’ll probably find the opening to the boiler is slightly (or severely) restricted with build-up.

If there’s no way to remove the bottom of the unit, you’ll need to work with a mirror to look into the boiler.

Valve assembly after clean-up.

To proceed with the clean-up of the valve body you’ll want to use ~300 grit sandpaper (emery cloth) and then 600 to finish off. You could use your Dremel / rotary tool with a fine brush attachment used for polishing brass (don’t use any compounds, just water) but you have to be very careful not to damage the threads or the valve seat, if you increase the original diameter there’s a chance the valve could pop in and float inside the boiler, allowing all of the boiler contents to spew out and it would never seal again forcing you to replace the entire valve head which may end up costing quite a bit of money and may not even be worth it on inexpensive units. Another possibility is for the bulb to catch and get stuck, so beware of the Dremel and abrasive tools.

After cleaning and polishing, it looks brand new!

If you want to make sure all the surfaces are neatly cleaned up and polished, you can use an old lead pencil as a former to wrap a piece of sandpaper around, tapering the top into a cone and then inserting it inside the valve body (with water) you’d proceed by twisting it a few times, removing it, inserting some cloth or paper towel wrapped around to clean up the valve and then take a look inside with a flashlight, repeat until it’s all nice and polished, specially the valve seat.

The silicone valve in my case had a lot of build-up but was easily removed by hand, don’t use any abrasives on it and try not to scratch it in any way.

Now that you’ve cleaned it all up, go ahead and add some water with the unit standing on it’s usual position and give it a few flushes, any loose pieces of build-up should come out, as well as anything you’ve unwillingly introduced while cleaning and polishing the valve body.

This is how the assembly goes, valve bulb/head pointing up.

If all looks good, go ahead and assemble the valve back to it’s original state. The silicone valve goes facing up into the valve seat, make sure the spring is nice and clean as well as the silicone valve head. If you see any damage on the silicone it’s time to replace the valve or come up with a makeshift solution…

Once it’s all assembled, torque the nut down making sure your diffuser disc / plate is in the right position and turn the unit on, give it a nice flush.

In my case the diffuser was slightly blocked so I had to clean it up with a needle and lots of patience before I installed it, This procedure made heaps of difference. Basically my espresso was not only leaky but also had low flow rate and it sputtered a lot making it difficult to obtain a straight shot with good crema.

Next in my list would be to access the pump to see if there’s a pressure relief adjustment and go ahead to calibrate it up to 9BAR at the head, that however is going to be a whole ‘notha quest for me. In that event I may probably end up refurbishing the pump as well.

Hopefully this guide has been of use to you!
And as you know, don’t send your machine to the store… A good barista fixes his/her own espresso!

Have a good one,
Gus

I didn’t quite reach my goal this year with regard to this site, however that doesn’t mean I’ll stop trying. I did get twice as many unique visitors compared to last year though, so that’s a fair win – Thanks to all of you for that from all around the globe!

Having dealt with the whole moving process pretty much on my own, being literally homeless for a short period of time due to lawyers and monkeys alike, it’s been a stressful one.

Priorities are now changing a bit.

I’ll keep trying my best to not to lose focus on the task at hand, I guess that’s a fair resolution for this new year, right? — Let’s be realistic at least!

Thanks again to those who have helped and to those who visit the site, I hope you’ve found what you were looking for, if not, let me know!

Have a good one.

Cheers,
Gus

Previously I’ve tried making my own adjustment tool with some brass tubing and solder, it worked for a while until the brass gave out and cracked all around. I also realised not everyone may have the right piece of tubing around, but more importantly I needed to adjust the carb on another engine and I still refused to spend a total of 30-40 US Dollars on the tool!

Now, it’s been suggested to just grab a Dremel tool with a cut-off disc and simply cut a couple grooves onto the screws, including the shroud — Well, I’m not too fond of this idea, but it got me thinking… what if I removed the screws, cut the slots, then put them back in?

That was the answer!. But how do we remove the screws, the whole point here is that we don’t have the tool to adjust the carb, let alone remove those pesky needle screws!

Well, I looked around and I noticed these old spark plugs in a box, some of them had a metal screw cap with the right diameter (almost, required some filing) this meant I could couple it to the pacman screws, but I still needed this makeshift tool to grab onto the notched screws.

The answer came by placing a thin piece of steel wire inside the original notch of the screw, once the spark-plug cap was inserted, it could grab ahold of the wire and allowed me to turn the damned screw!

The spark-plug being used as a temporary “tool” for needle screw removal. You may also notice the piece of steel wire on top of the needle, this is how the spark-plug cap binds onto the screw.

Low needle finally removed

I began by removing the L (Low) Adjustment screw/needle. After a few turns you can actually just remove it by hand. Obviously, the next logical step is to cut a slot onto it’s head. I did this by hand since the heads seem to be made out of aluminium or some mild steel (anodized alu is my best guess), so it’s rather easy to cut with most handsaws.

Close-up of the notched heads, excuse the poor quality of the picture — I improvised and I didn’t have the proper lighting, tripod, etc. at the time.

Once I got a deep enough slot, I decided to replace the needle and begin the whole process again with the H (High) Adjustment screw.

Before I put them back on though I added a bit of lithium grease onto the threads, perhaps not the best idea in the sense that this could make the needle not bind onto the brass insert and instead work itself loose with the vibrations of the 2 stroke engine, however I would rather have this happen than strip/damage the threads on the carb.

Be very careful with the needles, don’t scratch them, don’t bend them or stress them in any way.

Also I noticed the H and L needles were slightly different, the H had a tapered end whereas the L needle was straight.

Replacing them is simple, screw them all the way in, then go back 1.5 turns on each of them. This setting should be good enough to get the engine started on full-choke, you’ll have to then adjust the carb to get the right mixture on L and H.

 The only other alternative to this method would be to get the needles out, go to your local repair shop and see if they’ve got matching replacements with a slot head.

Adjust your carb

A basic adjustment routine is to begin with the 1.5 turns, choke it, start it. It may not stall at this stage, adjust the L screw until it does. Now restart and try to go WOT (Wide Open Throttle), adjust the H screw until the WOT sounds right (not too lean, not too rich). After this, adjust the L screw again, this time you are looking for a quick response from the throttle toward WOT. Stop the engine, restart, try it out and adjust the H again. Once it’s cold, repeat this process if you find the engine still doesn’t sound / operate right. It’s worth noting that any movement on the needles will take a few seconds to actually reflect on the performance of the engine, this lag is common and you have to learn to “wait for it” before you keep adjusting.

If problems still persist, perhaps this is a good time to rebuild your carburetor. There could be other issues such as a broken boot (this means there isn’t a good seal between the crank-case and the carb), broken/damaged gaskets are also common in this area. If the engine starves rebuild the carb. If it randomly shuts down, you should look into the ignition system. Other issues could be varnished gasoline inside the carb, this could also present you with random behaviour when bits of varnished gas lodge into the various components of the carb inhibiting it.

Closing up

Anyway, hopefully you’ll be able to find some old spark-plugs, some bits of wire and try this yourself before you butcher your engine with a Dremel tool!

Cheers,
Gus

It’s here!

The main-board for the LCD finally arrived, it’s a newer revision… all identical, except for a minor detail: the LVDS connector is different. <insert_rage_face_here/>

Oh well, I’ve yet to find a suitable LVDS cable for this panel, I think this is it for the LCD… Time to upgrade!

And on that note….

I was going to post a lengthy rant about how companies are always screwing us over but I realize it’s pointless to do so, we’d just be wasting bandwidth. Let’s instead focus on good things. I strongly believe open hardware is going to become mainstream. So I encourage you to share your projects whether they’re software or hardware related: post them somewhere, discuss them, get involved.

Don’t be afraid of “others making money off of it” there’s always going to be a weasel out there, you just have to look at the bigger picture.

In essence, nobody wins if everyone keeps everything to themselves. Be less secretive and more open. Go make something useful, go help someone out; you’ll be helping yourself in the process.

Cheers.

I recently got a free LCD that didn’t work, I went ahead and inspected the caps on the power supply, some were bad so I recapped it.
The LCD worked for about a week, then it developed a stuck pixel and suddenly it died again, same symptoms.

Couldn’t bring it back to life, so I decided to buy a new scaler board. Problem is, the actual part number is nowhere to be found, but I did find similar ones. Question is, are they compatible?

I asked the eBay seller, he didn’t know.

The journey begins…

Armed with the serial number We visited the Acer support site, just to find out a silly, paid “Answers” system, we went ahead and asked on IRC about support and got a chat URL, proceeded to enter the details of the product and ourselves…

Serial…

ETL23020224380047DED03

Is the product listed? yes. (Exact Model number was given)

We wait on queue for 4 minutes to chat with an “agent”… (Smith?)

Names have been changed. The agent was however Indian, I’m not being racist; just a bit humorous.

Indian Guy: Hi, my name is Indian Guy. How may I help you?
GuShH: Hi, I’m looking for a compatibility list on motherboards for this specific LCD. My supplier doesn’t stock the actual part number anymore, but I noticed there are lots of similar boards Acer made.
Indian Guy: I will certainly check our records and provide you the requested information.
GuShH: Thank you
Indian Guy: You are welcome, GuShH.
GuShH: I believe the original one was Acer MAIN BD.VL731.LAR598F.NO-IC
Item No.: 55.L23V2.051

GuShH: But there’s no stock left, only in the UK and the costs are too high for us.
GuShH: On this LCD the actual board is “JP577 VL-731 REV:1B”
GuShH: The VL-759 looks very similar, but I’m not sure if it’s compatible.
Indian Guy: I understand that, GuShH.
Indian Guy: GuShH, please note that Acer do not sell parts. However, I can give you part partners link where you can purchase all Acer parts for your computer.
GuShH: I’m only interested in the compatible mainboards for this particular LCD model. The supplier didn’t know which ones were compatible.
Indian Guy: All right, GuShH.
GuShH: (They don’t stock the original part number anymore)
Indian Guy: I can understand that, GuShH.
GuShH: Do you have a tech contact email for Acer LCDs?
Indian Guy: Yes, GuShH.
Indian Guy: I understand that you are looking for the motherboard which is compatible for the AL1912 b LCD monitor. Am I correct?
GuShH: Yes sir.
Indian Guy: Thank you for confirming, GuShH.
Indian Guy: I am searching for the information, GuShH.
GuShH: Thanks
Indian Guy: You are welcome.
Indian Guy: May I place the chat on hold for 3 minutes, while I retrieve the information for you?

GuShH: Sure
Indian Guy: Thank you, GuShH.
Indian Guy: I’m sorry it would take some more time. Please give me another 2 minutes.
GuShH: No problem
Indian Guy: Thank you, GuShH.
Indian Guy: GuShH, thank you for staying on line. I appreciate your patience.
Indian Guy: I checked our records, database. As you said there are many motherboards available in the market which might be compatible with this Computer monitor’s model.
GuShH: Question is which ones
Indian Guy: We do not have that information.
Indian Guy: However, we see that this computer monitor supports the resolution 1280 x 1024.
Indian Guy: To check the compatibility of the computer monitor.
Indian Guy: It is necessary that the video card in the motherboard should support the resolution which is mentioned 1280 x 1024.
GuShH: Could you tell me which monitor model this specific mainboard belongs to? VL-749 AR599GC
Indian Guy: I can understand that, I was not able to provide you the exact motherboard model which is compatible with the monitor.
GuShH: That’s the board the supplier currently has on stock.
Indian Guy: Unfortunately, we do not have that information.
Indian Guy: However, I cab provide the specification of the computer monitor which you are mentioned in the link provided: http://support.acer.com/acerpanam/monitor/0000/Acer/AL1912/AL1912sp2.shtml
GuShH: Thanks. On the other hand since I can’t find the specific mainboard for this monitor, I wondered if there’s a database where the mainboards are referenced to the model numbers of the LCDs, so I can find one that works for this product.
GuShH: I take it Acer does not design nor manufacture any of the internals, nor the actual LCD panel and it’s just a brand name then.
Indian Guy: I can understand your concern, GuShH.
Indian Guy: All I was able to find in our database is the part number for the model(AL1912 b) – ET.L2302.033.
GuShH: Alright thanks Indian Guy, hopefully I’ll be able to find some information with the part number ET.L2302.033.
Indian Guy: You are welcome, GuShH.
You have disconnected.

And then?…

Well, the given part number is useless, already had it — In fact that’s the number for the white version, the black version ends with 044. Was my question about a tech support email answered? — Not really.

And what is it with all the arse kissing these agents do?

Complete waste of time.

So here’s what I’m going to do… I’m going to order the board that “LOOKS” similar and is listed for this model, then I’m going to wait and hope it works when it does arrive; if it does arrive… Thing is, Aside from this board, there’s nothing else worth doing with such an old unit…

I’m aware about the multiple revisions and versions with multimedia options, different output interfaces and other crap. As long as the connectors are the same and it’s designed for a screen with the same or higher native resolution, it should work – In theory.

This isn’t how things should be done, I shouldn’t have to gamble on parts and “hope it works”… Why don’t you get your $$#% together, Acer? — And the same goes to every other company out there. If you don’t make it yourself because you are cheap and you’d rather have other companies bidding on your project requirements, at least make sure you get all the information you need and that you reference it with that particular product number and any other numbers that share the same or equivalent parts, so you may provide this information to technicians, alright?

Jeez.