Older ST-4 ROM update???

[Merlin66 (Ken)]

It would appear my original ST-4, doesn't have the V4 ROM chip nor provision for the addition of the desiccant ring.
Anyone know if it's possible to upgrade?????

[jase (Jason)]

In theory, yes. There should be nothing stopping you from upgrading the ROM to version 4B (latest) assuming SBIG still have the ROM's available. Considering v4B was released in 1991, your chances are grim. Email sbig@sbig.com to confirm. I think Linda Sasaki is in charge of the upgrade negotiations.

Failing that... Try a sell the camera and pick up a later version on astromart or get yourself the ST-402ME which will allow you to guide on much fainter stars.

[Merlin66 (Ken)]

Bill at SBIG has offered a V4 ROM upgrade!
Next question:
Has anyone got an ST-4 with a desiccant ring?? I need the dimensions to machine a suitable spacer for my older unit.
Many thanks,

[meade expert]

Hi All

For those with broken SBIG ST4 disicannt rings there is a way to manufacture a replacement.
The ring is 33mm by 23mm by 4mm thick. It is in technical terms an ANNULUS.

Surprisingly....there are at reject shops some stickytape plastic inserts that meet these dimensions almost exactly.

They are 33mm by 25mm by 10mm thick. They have a channel that is 2.2mm wide and 3mm deep (thats where you can pack tiny silica gel beads !)

So what you do is sandpaper down the ring till its about 3.5mm on its shallowest end and pack the beads into the deeper end, leaving a 0.5mm gap for air to get into the beads once it has been inserted into the nose piece slot.

Voila ! your replacement ring....and it works well!