2015's calculator anniversary - the SR-52

[jebem]

Hi, folks!

One year later I got my first Texas SR-52 too

Great beast of a machine! Fantastic! And of course it is not working.

My questions to the community:
Where or who can provide me a service manual?
What about spare parts providers?
Or any repair tips that you might have or know about would be highly appreciated.

I have repaired a number of Texas machines in my time, including the 59, but I have no knowledge of this one so far.

This machine was serviced at least once by the previous owner(s) and at least one unwanted mark was left inside.

Machine was swiftly and easily opened, as usual on Texas machines. After a brief initial visual inspection:
- The battery leaking corrosion have attacked the PCA, starting from the battery terminals.
- The battery electrolytic is visible in the card reader pinch roller and rubber wheel; also the card insertion switch sensor have small signals of corrosion as well.
- The BP-1A battery pack was rebuilt but is dead and leaked badly.
- The plastic frame that goes between the keyboard and PCA is broken and a piece of it is missing, typically of a careless dismantling by the previous owners or service.

The BP-1A battery pack was in fact nicely and professionally rebuilt with some red Ni-Cd cells "Made in Hong Kong", so it probably was done during the mid 80's or so.
However these batteries have leaked as well, corroding the PCA.
After opening the case, I have found one of the battery terminals lose inside.

The card reader looks like it may work after a good restoration.
The roller rubber is dry but still has traction, despite the horrible motor noise.
The R/W head four coils seems to be all fine:
L1 Orange - 742 Ohm, 0.15 Henry
L2 Green - 750 Ohm, 0.17 Henry
L3 White - 754 Ohm, 0.17 Henry
L4 Yellow - 756 Ohm, 0.18 Henry

Applying 3.6V from a power supply for just a few seconds gave me a satisfying "0" on the display, but as soon as I press any operators it goes blinking.
So the machine is faulty.
I will do a full cleaning on the PCA as usual and see if it helps, but I'm afraid that one or more IC's can also be faulty

More news to come one of these days.