Denial

Have you made sure the electrical contacts between the printer and the ink cartridge are clean (these look like a whole array of brass contacts, usually).

But the circuitry inside the ink cartridge itself might be dead (I believe some ink-jet printer ink cartridges have some sort of simple circuitry inside).

Thank you Ral-clan, I have tried both cleaning the contacts and changing the tank (I have six of them, all expired of course), but no luck .
Good news is: I found a Commdore MPS801 in Ebay from an Italian seller, 17 Euros incl. shipping. It is declared to be alive, i.e. the power light lights up. I already have some spare continuous feed paper and know which is the right ribbon to order (Seikosha GP-500). Can't wait to receive it for a true retro experience .

orion70 wrote:Thank you Ral-clan, I have tried both cleaning the contacts and changing the tank (I have six of them, all expired of course), but no luck .
Good news is: I found a Commdore MPS801 in Ebay from an Italian seller, 17 Euros incl. shipping. It is declared to be alive, i.e. the power light lights up. I already have some spare continuous feed paper and know which is the right ribbon to order (Seikosha GP-500). Can't wait to receive it for a true retro experience .

Hi! I'm glad you got an MPS-801. They are not fancy printers, but are very durable and have a very strong RETRO feel. They were also very common so new-old-stock ribbons are easy to get.

It might be a little better to get a VIC-1515 or 1520, which would match the VIC-20, but there are several disadvantages of the 1515 & 1520. I have a 1520, but I don't use it as it's VERY hard to get the strange ribbons these use. Instead, I use an MPS-801 for the reasons I stated above.

The MPS-801 is uni-directional, noisy, slow and doesn't have descending characters, but I actually LOVE all of those limitations because it feels so true to the very early 1980s when I use it.

TIP: Always keep your MPS-801 cartridges, even when they have dried up. The shells can be re-used. You can easily snap the cartridge shell open and replace the cloth ribbon with one from a more recent printer cartridge when the old one wears out (i.e. Panasonic KPX series and many other modern business dot-matrix printers use the same width of ribbon). You can also recharge the ink reservoir inside with a bottle of ink-pad stamper ink. Both the Panasonic ribbon cartridges and the ink bottles are available in office supply stores.

ral-clan wrote:Hi! I'm glad you got an MPS-801. They are not fancy printers, but are very durable and have a very strong RETRO feel. They were also very common so new-old-stock ribbons are easy to get.

Printer arrived, dirty but in good working order. No ribbon in it, so I ordered a couple of compatible ones. Received them today, so I'll test the printer asap.

ral-clan wrote:The MPS-801 is uni-directional, noisy, slow and doesn't have descending characters, but I actually LOVE all of those limitations because it feels so true to the very early 1980s when I use it.

Too true Ral-clan, especially if you keep the cover open the noise is higher than expected. I wonder how they could stand it in the average '80s office .

ral-clan wrote:TIP: Always keep your MPS-801 cartridges, even when they have dried up. The shells can be re-used. You can easily snap the cartridge shell open and replace the cloth ribbon with one from a more recent printer cartridge when the old one wears out (i.e. Panasonic KPX series and many other modern business dot-matrix printers use the same width of ribbon). You can also recharge the ink reservoir inside with a bottle of ink-pad stamper ink. Both the Panasonic ribbon cartridges and the ink bottles are available in office supply stores.

I didn't try to open a new cart of course, but it's a good tip for the future. Thanks. Is it better to change the ribbon, or re-ink the reservoir?

orion70 wrote:I didn't try to open a new cart of course, but it's a good tip for the future. Thanks. Is it better to change the ribbon, or re-ink the reservoir?

It is always better to re-ink the cartridge, and put a few drops on the ribbon as well. I've seen a few different internal designs of MPS-801 cartridges, but many have a little extra plastic container inside the cartridge that contains and ink-soaked sponge (I think on one design it is a ink-soaked sponge wheel). As the ribbon cycles past this reservoir, it is constantly re-inked by the sponge/reservoir until the reservoir is dry. So once the reservoir is dry you inject (with a syringe or squirt some ink-pad ink into it to recharge it). Ink pad ink is oil based NOT water based, so it doesn't dry in the air and won't destroy your print head.

If you only re-ink the ribbon, it will be good for a short while, but will quickly fade as it's not getting recharged from the reservoir every time it cycles through the cartridge.

I admit that I have not had to do this often because I really don't print that much. But I've had my MPS-801 and many of the cartridges open a lot (I've even taken pictures of all the internals of both if you need to see the differences). So I've given this a bit of thought.

ral-clan wrote:But I've had my MPS-801 and many of the cartridges open a lot (I've even taken pictures of all the internals of both if you need to see the differences).

Yes please, it would be great if you could post here and/or in the newly created MPS-801 wiki page .

orion70 wrote:

ral-clan wrote:But I've had my MPS-801 and many of the cartridges open a lot (I've even taken pictures of all the internals of both if you need to see the differences).

Yes please, it would be great if you could post here and/or in the newly created MPS-801 wiki page .

Well done on that page. I will try and remember to insert my pictures of the MPS-801 (internals, etc.) on it in the next few days.

A small update about my mps801 printer. The new compatible ink arrived from an Amazon affiliate a couple of days ago. I managed to try it yesterday after work (I still have the printer at my workplace), but it doesn't seem to operate correctly .
The ink cartridge is OK, it fits perfectly in the printer, and seems to be full of fresh ink. When I turn the printer on in Self Test position, the first half line is printed quite clearly, but afterwards it seems to dry out and nothing more appears. When I print with no ink cart, I can see the ribbon shaft correctly revolving (arrow):


...but when I try with the ink cart, even if I am sure it fits the shaft, during the print the ribbon does not move. For some reason, the shaft is not "strong enough" to carry it, or maybe the shaft is worn out? Take a look at the picture below, a view of the carrier unit without the ink cart:


My problem is, I have never seen working mps801 or pictures of the internals, so I don't even know if mine is OK. For example, from the tech manual I understand that the paper thickness is regulated via a lever on the left, which is kept in place by a "foot" secured in a "click hole":


...but my printer has a (very loose) lever and NO foot to put inside the hole:


Finally, here's an overall view of the printer internals with the ink cart, just to make sure nothing else is missing:


I'm afraid I'll have to look for another printer - too bad, because I really like this one and electrically/mechanically it seems to work.
Thanks for any help.

Okay, there are a couple things I can think of....

Your printer looks fine and there should be no "metal foot" for that lever. However, the lever should not be so loose it is floppy. It should move very easily, but click into several positions as it moves along the cut-out arch shape. (correction: looking at my pictures below I can see there is a metal foot on THE INSIDE of the printer - not visible when assembled).

When the printing fades out, is new ribbon still being drawn through cartridge and across the print head, or has the ribbon stopped feeding?

Do you think there might be something that prevents the cartridge from seating itself properly against the driving spur on the carriage bed?

This might be a motor problem - weak old motor (the motor is at the far left of the carriage rails when the printer is open.
Or perhaps the long, toothed belt is slipping (it drives the carriage).

Can you still hear the print head engage all the way along paper as if the pins are still striking the paper? Or does the print head also give up trying to print just where the ink fades out on the paper?

Have you opened up the ribbon cartridge to make sure there is not a problem with the ribbon inside the cartridge? Perhaps it is stuck or caught somehow inside the cartridge. The cartridge should pop open fairly easily. Just be careful you don't let the ribbon (which is accordion-like inside the cartridge) to spill out.

Perhaps the little cross shaped hole on the bottom of the ribbon cartridge is worn and not engaging tightly with the drive spur. Perhaps the gear driven by this, inside the ribbon cartridge, is stuck.

Could also be the large capacitor on the motherboard of the printer is dried out and needs replacing. Maybe it's not able to drive the motor properly - although if the carriage is still moving back and forth this is unlikely. You might want to look at them and see if they are burst or swollen (but it might not be evident if they are just dried out).

Is there anything you can lubricate moving parts with? A little WD40 (do you have it there?) - a synthetic spray lubricant, or a light synthetic machine oil. Just be careful when spraying it to only put it on the metal moving parts (WD40 here come with a thin red straw to aim it at small components). Do not use organic lubricant oil - it could harden or gum up in future.

If this printer is not salvageable, I would still keep it and get another MPS801. You can then use the parts (print-head, etc.) as spares for repair jobs in the future. BUT, there's not a lot inside the MPS-801 so I think it is likely this can be repaired (if the failure is mechanical in nature - which it seems).

I will try and help you if I can - let's diagnose this.

Here are some images of my MPS-801 when I had it open (click on enlarge):

Two designs of cartridges:










Circuit board with capacitors. The stuff at the bottom of the capacitors is merely adhesive and is normal - but if you see something at the top bursting out, that is not good.

Great! Let's try

ral-clan wrote:Your printer looks fine and there should be no "metal foot" for that lever. However, the lever should not be so loose it is floppy. It should move very easily, but click into several positions as it moves along the cut-out arch shape. (correction: looking at my pictures below I can see there is a metal foot on THE INSIDE of the printer - not visible when assembled).

That's it! I can see something like an internal foot through the holes, but it's not tight enough to actually enter the holes. I will open the printer the way you did, and manipulate the lever e.g. pressing it against the metal sheet where the holes are.

ral-clan wrote:When the printing fades out, is new ribbon still being drawn through cartridge and across the print head, or has the ribbon stopped feeding?

Maybe I wasn't clear in the description, sorry for that: the ribbon is ALWAYS still, I never see it fed across the print head. That's the main problem IMO: even if without the ink cart I can see the ribbon shaft revolving, when I put the cart on, the ribbon doesn't run.

ral-clan wrote:Do you think there might be something that prevents the cartridge from seating itself properly against the driving spur on the carriage bed?

The only thing I can think about is that the cross-shaped shaft and/or the clips keeping the ink cart are worn out, so the ink cart doesn't seat properly in the carrier unit.

ral-clan wrote:This might be a motor problem - weak old motor (the motor is at the far left of the carriage rails when the printer is open. Or perhaps the long, toothed belt is slipping (it drives the carriage).

Hope not

ral-clan wrote:Can you still hear the print head engage all the way along paper as if the pins are still striking the paper? Or does the print head also give up trying to print just where the ink fades out on the paper?

Yep, the print head goes on with its noisy job all the way to the end of the lines, and nope, it never gives up (fortunately).

ral-clan wrote:Have you opened up the ribbon cartridge to make sure there is not a problem with the ribbon inside the cartridge? Perhaps it is stuck or caught somehow inside the cartridge. The cartridge should pop open fairly easily. Just be careful you don't let the ribbon (which is accordion-like inside the cartridge) to spill out.

I only have two of them, and don't want to risk their life. But when I manually turn the knob, the ribbon moves.

ral-clan wrote:Perhaps the little cross shaped hole on the bottom of the ribbon cartridge is worn and not engaging tightly with the drive spur. Perhaps the gear driven by this, inside the ribbon cartridge, is stuck.

Unlikely. I can manually rotate it with a screwdriver, and the cart is new..

ral-clan wrote:Could also be the large capacitor on the motherboard of the printer is dried out and needs replacing. Maybe it's not able to drive the motor properly - although if the carriage is still moving back and forth this is unlikely. You might want to look at them and see if they are burst or swollen (but it might not be evident if they are just dried out).

This paragraph goes into the unknow fields of electronics . I'll check whe I'll open the printer.

ral-clan wrote:Is there anything you can lubricate moving parts with? A little WD40 (do you have it there?) - a synthetic spray lubricant, or a light synthetic machine oil. Just be careful when spraying it to only put it on the metal moving parts (WD40 here come with a thin red straw to aim it at small components). Do not use organic lubricant oil - it could harden or gum up in future.

My colleague here at work has light synthetic oil for musical instruments (she plays the Flugelhorn ). I'll eventually try with it.

ral-clan wrote:If this printer is not salvageable, I would still keep it and get another MPS801. You can then use the parts (print-head, etc.) as spares for repair jobs in the future. BUT, there's not a lot inside the MPS-801 so I think it is likely this can be repaired (if the failure is mechanical in nature - which it seems).

I'll try my best. Thanks again Ral-clan, til next update!

When you send a print command to the printer with no ink cartridge installed, can you see that the little cross-shaped drive spur is actually turning as it should?

If so, can you try and put your finger on the drive spur while the printer is fake-printing and see if you are able to stop it turning. If so, perhaps this means the gear driving this spur is weak or slipping. Perhaps it the drive gear is cracked (plastic gear) and spinning on its metal shaft when it shouldn't.

If you feel confident in doing so, I would try and carefully disassemble the carriage to see what could be making the drive spur weak like this. We need to see what is underneath that drive spur that is the problem.

At this point, I am assuming the problem is in the carriage, underneath the drive spur. I assume this because the drive spur is not driving the ribbon-feed, but the carriage moves back and forth without issue. If the carriage wasn't moving back and forth I might suspect the drive gear on the motor side.

Also, when you use a screwdriver to turn the spur-hole on the bottom of the ink-cartridge, does it turn easily and make the ribbon move without you having to exert too much strength? If you really have to turn with a lot of resistance, then there might be something wrong with the ribbon.

I assume you have tested with both ribbons and the same problem occurs?

What is the condition of the "teeth" on the drive belt? Are any missing?

But first try your lubrication and other things you were going to try.

Lots to do next monday (I left it @work). Will edit this post..
[EDIT]

ral-clan wrote:When you send a print command to the printer with no ink cartridge installed, can you see that the little cross-shaped drive spur is actually turning as it should?

Yes...

ral-clan wrote:If so, can you try and put your finger on the drive spur while the printer is fake-printing and see if you are able to stop it turning. If so, perhaps this means the gear driving this spur is weak or slipping. Perhaps it the drive gear is cracked (plastic gear) and spinning on its metal shaft when it shouldn't.

...and yes, the drive spur actually stops even with the slightest press of a finger
Everything else looks OK, maybe the printer doesn't even need to be lubricated. And the ink tanks are OK, too.

ral-clan wrote:If you feel confident in doing so, I would try and carefully disassemble the carriage to see what could be making the drive spur weak like this. We need to see what is underneath that drive spur that is the problem.

I feel confident, but actually can't do it. The screw caps of the printer plastic chassis, which is the first thing to open, are worn out and I am not able to unscrew them even with the strongest screwdriver
In your opinion, is there a way to disassemble the carriage directly from above, without opening the printer plastic?

[in the meanwhile, running out of patience, and compulsively looking for other stuff in ebay ]

The best way to remove the screws is using a drill/extractor combo, like one of these:

http://www.amazon.com/gp/product/B001A4 ... B001A4CWHO
http://www.amazon.com/Alden-4507P-Grabi ... y_hi_img_y

Basically they're a two sided tool: on one side you have some sort of special drill bit that will perforate the screw's head in a peculiar way; it is also self-centering so it won't (usually) slip all around. On the other side you have a special counter-clockwise filed screw that will grip very hard on the previously drilled screw head.

I suppose you may also get one of these sets by going to your local Ferramenta™ with your Lambretta™...

Personally I'd be rougher and I would simply drill the screws' head with a standard steel (HSS) drill bit, until the head is completely wiped off and only the shaft remains. The case should then open easily. After that I would remove what remains of the screw shaft with a pincer. The old screws will be easily replaced with common "Parker"-type screws of the appropriate size and length. Drill at slow speed and alternating the screws on which you are drilling: the metal shall not overheat and melt the plastic case as a consequence.

Phew! Thanks a lot for the tips. As for the screw extractor, I'd better buy a new printer or two kilos of gelato al limon™ for the price, so I'll skip this one. If no other solutions are viable and the problem persists, I'll eventually try with the driller - hoping it won't cause a complete mess .

Well, broken as it stands, you can't break it any further, correct?

broken traction pulley = broken printer

broken traction pulley + scrapped case = broken printer

PS: I'm very happy about your plan of rebuilding your VIC corner, fellow.