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Malvern Particle Sizer - CBM 8296 OEM


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  Malvern Particle Sizer - CBM 8296 OEM by Bill Degnan - 01/10/2009 11:52
I have re-started the restoration of the Malvern "Particle Sizer" a CBM 8296 OEM unit from an earlier thread. This is no normal 8296, it looks more like a squashed 8032. In addition to the strangeness of the chassis (compared with the normal 8296), this computer has a daughter board for Co-ax communications and/or particle sizing? with an end port similar to an IBM PC. The true origins of this OEM system is proven by the 8296 label, motherboard part number 324645, and a single internal SFD-1001 drive. Note that since some of these pictures were taken a few years ago I have fixed up some of the dangling bits. Ignore the file dates, they were changed when this web site was moved in Jan 09.

I have tested the power and found issues. It will not boot (only once did it boot to the BASIC prompt). I believe it's set to US power but the manufacturer, Malvern, is an English company.

Closeup of the "LASER" PSU 106 used in the Malvern. This is not a stock CBM part. Click image for larger version.

Restistor Readings (pairs of terminals from left to right)
LM317 left -1.255v
right 9.98v

LM337 left 2.5v
right 1.17v

LM4807 left 11.99
right 5.00

The plastic device under the restistors, labeled "SPECTROL |2 CM", smoked for a while, but stopped and is either burned out or no longer smokes. The diode next to it, with the discoloration has been cleaned off since this pic was taken.

The 2200uf 25V capacitors at the top of this photo (clockwise)

-12v, -24v, -24v respectively.

More pictures from a few years ago and Even more pictures. NOTE: Only the pictures with a 2009 file date are new; this web site was moved and the file dates were changed during the move.

  PLA Replacement Malvern CBM 8296 by Bill Degnan - 01/11/2009 11:53
Mike Nab. sent me replacement PLA chips for this computer, but I am going to hold off on testing them until the power issues are resolved. One thing I noticed is that only one of the PLA's is socket-ed (ug).

The motherboard is definitely the standard 8296 (see

PLA area of the motherboard after removing the Malvern daughtercard.



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