Sun 2/50 - S/N C-1091 - tallinn
8 February 2014
- Archive Sidewinder activity light stays dark when powering on Sun-2 Shoebox
- Sun-2 Mouse Compatibility
- Sun-2 Shoebox becomes very hot
- 3 MB memory board fails diagnostic test
Archive Sidewinder activity light stays dark when powering on Sun-2 Shoebox
When powering on the Sun-2 Shoebox, the red activity light above the QIC tape slot fails to illuminate while the drive initializes (this is only observable if the top cover has been removed from the shoebox). The tape drive does not come online or otherwise respond to the system.
The 24 volt power supply has failed. It outputs zero volts at the drive power connector.
Replace electrolytic capacitor C14, near the DC output wiring harness. It is rated 2200 µF, 35 V.
Sun-2 Mouse Compatibility
The Sun-2 mouse is easily spotted, as it is black with white buttons instead of all white like later Sun mice, but it is quite difficult to find.
If one is found, the problem then becomes to find a suitable optical mouse pad: the Sun-2 mouse comes in two distinct models. One model is derived from the Mouse Systems M2 mouse, identified by the "M2" designation on the model tag and having its two optical apertures close to each other and near the central longitudinal axis of the mouse. The other model is derived from the older Mouse Systems M1 mouse, identified by the "M1" designation and having its two optical apertures spaced farther apart and canted at a 45° angle with respect to the left and right edges of the mouse.
The older M1 mouse can use only the M1 style mouse pad, identified by having a coarse grid of blue vertical and red horizontal lines (though these latter may be so severely faded that they appear almost invisible). The M2 mouse can use either this style pad, or the newer M2/M3 style pad which has black horizontal lines instead of red. Though more common than the M1 style pad, the M2/M3 style pads are still difficult to find.
The Solbourne mouse—which, like the Sun-4 mouse, is based on the much newer Mouse Systems M4—retains the RJ11 connector of the Sun-2 mouse and is, in fact, fully compatible with the Sun-2. I'm not sure whether it's any easier to find, but it does have the advantage of using the same optical pad as the Sun-4 and Sun Type 5 mice (fine grid, blue and black lines, though possibly appearing all blue or all black without the aid of magnification and/or strong lighting) which are quite commonly found.
Sun-2 Shoebox becomes very hot
After running for twenty minutes or so, the Sun-2 SCSI Shoebox becomes very hot. It is nearly too hot to touch.
The exhaust fan has failed. It may be observed to run when the shoebox is first powered on, but after a minute or two it slows to a stop and the shoebox can no longer be adequately cooled.
The exhaust fan is a standard 120mm 12V DC brushless model, with a 2-position Molex Standard .062" type connector. The replacement should draw no more than 0.25A and be no thicker than 1.5".
3 MB memory board fails diagnostic test
When configured for use with a 4 MB CPU, the 501-1067 3 MB VME memory board fails self-tests with the following message.
Self Test found a problem in memory [addr] Wrote 100001 at address 4FFFFC, but read 0. 1048568 total errors. Damage found, memory (constant data) (address independence)
The 501-1067 3 MB VME memory board is designed to be used with a 1 MB CPU, to provide 4 MB of total system RAM. It cannot be jumpered to work in any other configuration, because the first memory bank of the 501-1067 is not populated.
In order to use this board with a non-1 MB CPU, two ECO wires must be installed, so that when the CAS lines for the 1st memory bank are decoded, they are routed instead to the 4th bank (with the configuration jumpers installed correctly, the 4th bank will never otherwise be activated). A generalized and abbreviated schematic diagram of the various Sun-2 VME Memory Boards is linked below, showing the necessary ECO work in red.