Tech. Bulletins (click here to return to list)

1. OVERVIEW

When running the basic slope procedure with TDP0 C/M, the resultant prints should exhibit an overall trend in slopes. A couple instances that FINISys was involved in, showed significant slope behaviour of the films printed, especially in overs. The results were more like a "rainbow", as different films showed significantly deviant slopes (starting upwards from about the number 7 test negative), that could not possibly be corrected by the basic slope. Problem diagnostics and analysis showed that in both cases the scanner was the culprit.

2. DIAGNOSTIC PROCEDURES

To check the proper functioning of the scanner, use a Gretag 11 test negative strip and run with OMUL P and OPND CALC. Compare the results of the number 11 (over) negative from one scan to the next - scanned values of I _b / I _g / I _r should vary less than +/- 0.05d from one scan to the next. Also observe the DEN information given for FL1, which should remain approximately stable (+/- 0.05d) from one scan to the next.

To establish whether other parts of the scanning system are possible causes, a comparison to other printers can be helpful: compare scanned results to a known good printer (with the same type scanner) - differences should be less than 0.10d in any color.

A problem deteced when using this procedure may lead to 2.1., 2.2. or 2.3. below.

2.1. SCANNER POWER SUPPLY

The scanner logic power supply SP15 (+/- 15 V 0.5Amps) has a prescibed maximum AC ripple (noise) that is allowed (use correct ground when measuring !) :

0.005 VAC with Multimeter or 0.030V pp with Oscilloscope

If the AC voltage on the positive and/or negative supply exceeds above limits, the power supply must be replaced. Also note that older machines had a supply that is insufficient (0.35 Amps) when run together with a DX reader.

Other symptoms of a possible malfunction of this supply are inconsistent OSCN readings, that are not stable from one scan to the next.

2.2. SCANNER OPTICS

The beam splitter mirrors in the lower scanner must be installed correctly:

• The reflective coating must be facing the light source
• The mirror must be installed so that the retaining clips on either side face in the same direction and down (away from the light / scandisc).

The Blue tubus’ scanner filter (supplied with the FINISys upgrade) must be inserted as far as is possible into the tubus. If it is not fully inserted, light may leak around the side edge of the filt

A black aperture ring (supplied with the FINISys Scanner Upgrade) must be installed under each dichroic filter (towards the measuring cells). They serve to mask the oncoated edge area of each filter.

2.3. SCANNER SYSTEM

The scanner system comprises the Upper Scanner and Lamp Power Supply, the Lower Scanner, the Filmdeck (format), several logic pcb’s (MESCO/MESKA, MESMO/MESUR, COMIS/COMIC A [3141/3140], MESRA and MESZA) and the SP15 power supply. Any of these can temporarily be swapped with another printer for troubleshooting, but should be put back into the original printer, so that Paper Matrix and Basic Slope are not affected in other machines.

3. ADDITIONAL INFORMATION

Once the problem has been identified and corrected, the Basic Slope procedure (TDP0 C/M) must be run again. Unless components listed in 2.3. above were changed, the Paper Matrix (TDPM) should not be affected.

If the SP15 power supply was found to be defective, the Paper matrix may have to be run also.

This page last modified: May 08, 1997
copyright FINISys Inc. 1997, author: R. Ganahl