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Category: Recap / Capacitor Lists


Floppy drives have an sensor to detect track zero position which tells the drive the positioning of the first track on the disk(hence all tracks). On some drives it is mounted on the same PCB as the capacitors and removing the PCB will dislocate the adjustment for track 0. If the screw holes for the PCB are elongated (thus allowing for adjustment) then there is a good possibility the track zero sensor is on the PCB.
One way to determine bad track zero adjustment is by formatting a disk on that device. It will manage to read and write a disk formatted by itself, trying to read a disk written on another known good drive will fail because the track offsets differ.

Adjustment of the zero stop should be done using proper equipment and not by trial and error.

.. in other words, (TL;DR) do not touch the track zero sensor adjustment 🙂



Assuming there are no mechanical faults, the symptoms are intermittent failures/halts or read errors, buzzing noise when moving R/W head (motor not able to move properly) or even totally dead.

Some drives allow for capacitors to be relocated to the other side of the PCB which might provide a better environment and space for capacitors with better specifications.
Before continuing, make sure to read the warning about TRACK ZERO SENSOR above.








Philips Videopac G7000/22

As with all aging electronic equipment and capacitors, it was time to give my G7000/22 internal PSU a maintenance. The G7000 operates on +5V and the original PSU output between 7.2V to 8.2V unloaded. Even though I documented the capacitors, I decided a replacement +5V SMPS would be a better choice.

Replacement +5V SMPS, a reversible modification.

Electrical Shock Hazard

Work should not be attempted if not having experience with
powersupplies and understanding the dangers with it.




Electrical Shock Hazard

Work should not be attempted if not having experience with
powersupplies and understanding the dangers with it.




The original fan is noisy and can be replaced with a 80mm silent one, you need one with a 3-pin connector. The pin order is not the same, match red to red and black to black. I added a Noctua 3-pin low noise adapter (NA-SRC10) in which I removed the yellow cable and corrected the pin order.


Main board




Memory expansion



Tape PCB




As a normal precaution, I disconnected the motherboard from the PSU and when powering it up, every fuse on the board blew. All three large capacitors were shorted.

The large capacitors have 4 legs, middle pin is positive (+) and the outer ring legs are negative.

Positive pin marked with red, and negative pins marked with green.
You can replace these with a standard 2 leg radial capacitor (r=11), just make sure the negative planes have continuity.

After a full recap and replacing the rectifier bridge (with better specs to run cooler) the PSU powered up and gave stable +5/+12/-20V.


Wires from the transformer to the PSU PCB were brittle and snapped off just by touching them.

New solder, shrinking tube and a zip-tie to the rescue.