For the benefit of anyone (such as Richard) with a broken or malfunctioning OPD mono monitor :
>Pressing the "standby" button results in a chattering OPD - >otherwise, it's silent with the phone lines pulled high and no video output. > >I'm going to check for pinouts. Voltages don't scare me (used to work >on Macs), but I rarely have time to mess with repairing kit these days! > >Richard For details of OPD pins outs, please see the 'display' heading under : http://www.nvg.ntnu.no/sinclair/computers/clones/opd.htm "Display A D15 cable connects the console to the monitor, bringing in power lines from the PSU and carrying back RGB TTL colour signals. The 15 pins of the D connector to the monitor are as follows: - to the display: D1=0V; D2=Red: D3=Green; D4=Blue; D5=H-sync; D6=V-sync; D10=on indicator; - from the PSU: D7=OV; D8=5V; D11=+5V; D12=+5V; D13=+12V; D14=+5V. Details of OPD power supply and pin outs appear under section 1.8 of Murray Macabes comprehensive (circa 1990) write up : http://www.binarydinosaurs.co.uk/Museum/icl/murraywriteup.php "VDU (Monitor) : mono monitor powered from ASTEC card (+5V 3-3.5 Amps; +12V 1.5 Amps; -5V 0.1 Amps) " I found the following useful tips on repairing OPD mono monitors. These notes were compiled by the OPD enthusiasts group (circa 1993) : a) "Non linear compacting of the vertical scan leads to half of the picture appearing in the top 1cm of the screen .... this was cured by the replacement of degraded capacitor C10" Tip : If the screen is blank or compacted, it's almost always the fault of the C10 capacitor. These are cheap and easy to fix. Replacement electrolytic capacitor are available from Maplin or RS for less than £1. b) The OPD requires +12V, +5V and -5V. Power, sync and video lines are fed from the monitor to the OPD base unit via a 15 way D connector. c) Wires going from the main PCB, via an ICL add on that mixes the RGB signal to grey scales with contrast control : White : H-sync; Blue : V-Sync; Brown - intensity; Purple - 0V; Orange : +12V. d) The intensity goes off to the tube PCB (on grey); H-sync mates up with three transistors and the 555 timer, running the horiz. scan coils and the line transformer via the BU806 transistor; V-sync goes to the TDA11705 and through the infamous C10 to the vertical scan coils. Dan. --------------------------------- All New Yahoo! Mail Tired of unwanted email come-ons? Let our SpamGuard protect you. _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
