FM Towns:Desktop Power Supply Repair and Capacitor list
Desktop Power Supply Repair
FM Towns Desktops used different power supplies in different models. It is very important you pay attention to the model you have.
It is also important to understand that FM Towns computer is always in standby mode with 10V (running in the 12V pins) and 5V always powering the computer even when it is off. This will strain the already aging components even more. It is recommended to unplug the computer if you're not going to be using it for a long period of time. You're also recommended to use a 100V stepdown even if you're in a 120V country because FM Towns Power Supply is not regulated like an ATX Power supply. For example, having 7.3V going down the 5V line when plugged into 120VAC is not a good thing.
HG/HR Model Power Supply
Should look like this picture. Console5 sells a capacitor kit for this PSU model.
Note that C7 must be no taller than 44mm? and spacing is about 7mm.
| Name | Microfarad | Voltage |
|---|---|---|
| C7 | 680UF | 200V |
| C59 | 220UF | 50V |
| C60 | 220UF | 35V |
| C62 | 10UF | 50V |
| C66 | 2.2UF | 50V |
| C69 | 10UF | 50V |
| C57 | 2200UF | 10V |
| C58 | 2200UF | 10V |
| C52 | 1000UF | 25V |
| C53 | 10UF | 50V |
| C54 | 10UF | 50V |
MA/MX PSU
The desktops with 4 expansion slots in the back. It should be noted there is a bipolar capacitor in this power supply. Console5 sells a capacitor kit for this PSU.
C5 should have between 7mm to 10mm spacing and be relatively short. Can't remember the spacing. If you get a replacement with capacitors legs, they can be bent in a way to make it fit.
| Capacitor | Microfarad | Voltage |
|---|---|---|
| C5 | 820uF | 180V |
| C12 | 39uF | 35V |
| C14 | 1500uF | 25V |
| C15 | 220uF | 25V |
| C16 | 3300uF | 16V |
| C17 | 3300uF | 16V |
| C18 | 3300uF | 16V |
| C19 | 470uF | 16V |
| C20 | 220uF | 35V |
| C21 | 100uF | 25V |
| C24 | 220uF | 25V |
| C25 | 47uF | 25V |
| C26 | 1uF | 50V |
| C27 | 1uF | 50V |
| C28 | 1uF | 50V |
| C29 (BIPOLAR) | 1uF | 50V |
| C30 | 1uF | 50V |
| C33 | 1uF | 50V |
HA/HB/HC or Pentium Towns PSU
Structured oddly with two separate wiring harnesses. C34 near the black relay will generally leak badly just like the other FMT Power Supply. C06 requires 10mm spacing between leads which is the supercap in the photo. Everything else can use 5mm spacing.
| Capacitor | Microfarad | Voltage |
|---|---|---|
| C34 | 470UF | 25V |
| C30 | 470UF | 25V |
| C27 | 330UF | 25V |
| C05 | 1200UF | 180V |
| C07 | 47UF | 50V |
| C33 | 470UF | 10V |
| C29 | 1000UF | 25V |
| C26 | 1000UF | 25V |
| C24 | 2200UF | 10V |
| C23 | 2200UF | 10V |
| C22 | 2200UF | 50V |
EA/ME PSU
The desktops with 3 expansion slots in the back. Again the capacitor near the black relay will have spilled if it had a lot of use as well as the tall capacitors near the wiring harness.
| Capacitor | Microfarad | Voltage |
|---|---|---|
| C5 | 820UF | 180V |
| C12 | 39UF | 35V |
| C15 | 220UF | 25V |
| C14 | 1500UF | 25V |
| C16 | 3300UF | 16V |
| C17 | 3300UF | 16V |
| C18 | 3300UF | 16V |
| C19 | 470UF | 16V |
| C20 | 220UF | 35V |
| C21 | 100UF | 25V |
| C24 | 220UF | 25V |
| C25 | 47UF | 25V |
| C26 | 1UF | 50V |
| C27 | 1UF | 50V |
| C28 | 1UF | 50V |
| C29 | 1UF | 50V |
| C30 | 1UF | 50V |
| C33 | 1UF | 50V |