New project: An ACT Apricot F1 "barn find"

[stephen_usher]

That's for later, once I get the drive stable enough to be recognised properly and permanently and get the motor spinning.

Those are trims for the signals from the heads, from the description.

One thing at a time.

[rubber_jonnie]

The variable items look like resistors based on the silk screen, so probably ok.

May be worth giving them a tweak back and forth in case you already haven't due to the opportunity of corrosion getting to their tracks and the wiper.

I had thought this after I posted, but make sure you mark them first so you can get the original position back. Maybe even a drop of contact fluid.

[stephen_usher]

OK, those capacitors replaced and no change...

However, when I turned the board over I dicovered a whole load of surface mount tantalums! Worse, they're not marked at all! I think that they're tantalums anyway as they're brown in colour, though the lack of obvious polarity may suggest that they're merely ceramics.

[stephen_usher]

Does anyone know what this component is?

IMG_2317.jpg (23.45 KiB) Viewed 3107 times

I'm thinking about removing it as a test and seeing what happens.

[Tomswork]

My guess is terminator resistor

Tom

[stephen_usher]

It seems to be some sort of capacitor matrix. Anyway, removing it made no difference.

I then decided to try the freeze ray^H^H^Hspray. (OK, well, it's an air blower but if you turn it upside down it outputs liquid propane.)

No change on any of the 74xxx chips but... Dribble some on the main controller chip, wait for it to freeze and... The drive responds correctly. The Apricot seeks the heads and determines it's the correct size.

Bother! If it's the bespoke controller chip gone bad then it's a dead duck.

[rubber_jonnie]

Does anyone know what this component is?

I'm thinking about removing it as a test and seeing what happens.

Looks like boobs to me

If it's removable then it could well be a termination resistor as @Tomswork suggests.

Can you trace it and see what its connected to, such as data lines?

[rubber_jonnie]

It seems to be some sort of capacitor matrix. Anyway, removing it made no difference.

I then decided to try the freeze ray^H^H^Hspray. (OK, well, it's an air blower but if you turn it upside down it outputs liquid propane.)

No change on any of the 74xxx chips but... Dribble some on the main controller chip, wait for it to freeze and... The drive responds correctly. The Apricot seeks the heads and determines it's the correct size.

Bother! If it's the bespoke controller chip gone bad then it's a dead duck.

Oh no, that's rubbish

[DoG]

Does anyone know what this component is?
...

What does the silk screen says it is?

[stephen_usher]

Does anyone know what this component is?
...

What does the silk screen says it is?

L and then a number. It seems to be a matrix capacitor thingy.