forum.defence-force.org

Well, usually you either got a picture full of scrambled (sometimes even colorful and flashing) squares and bars and the Oric does not boot, or it boots but hangs or makes strange things. Of course it may not generate an RF image and a SCART cable may help.

If the Oric boots it usually makes sounds when clicking keys (unless the AY or the amplifier or the speaker is gone). In fact it is the best way to check if an Oric boots when you have no picture. Just plug the lead, wait and press some keys to hear the click... then try ZAP or PING.

But both at the same time... that is bad luck. Moreover when you checked the regulator and discarded it. Even a diagnostic ROM wouldn't help.

It is really hard to tell, but the usual step here is checking all the VCC/GND pins in chips for 5 volt. Maybe there is a damaged track, a burnt chip or component, but it is indeed something that requires a systematic review. Starting for the components which are closer to the regulator. Maybe checking for continuity along the GND rack is also a good idea.

Chema wrote: ↑Fri Mar 01, 2019 7:55 pm It is really hard to tell, but the usual step here is checking all the VCC/GND pins in chips for 5 volt. Maybe there is a damaged track, a burnt chip or component, but it is indeed something that requires a systematic review. Starting for the components which are closer to the regulator. Maybe checking for continuity along the GND rack is also a good idea.

I second that. In the arcade repair world, the golden rule is "ASAP", which stands for "Always Start At Power".

This basically means to verify that your power supply is working correctly (which it does for you since it works on another Oric), then to verify that all power connections are sound.

Chema mentioned checking the voltage at all the VCC pins of every chip but I would do that as a second step. Before that one, I would first verify that there is continuity between the +5V provided by the regulator and every chip on board:

- set your multimeter to "continuity testing" (usually has an speaker icon) and verify that the regulator +5V pin is connected to the VCC of every chip
- similarly, verify that the regulator GND pin is connected to the GND pin of every chip

Remember that this must be done with power off, to avoid accidental short circuits on the regulator pins.

If your multimeter does not have a continuity mode, you can use the resistance measure mode and verify that there is a zero resistance between the above mentioned points.

I don't surpose someone could let me know which pins on the chips are vcc and which ones are Gnd I have had a look at a schematic but I not very good at reading it.
Many Thanks

Hi,
do you know how to read a chip and how to identify its pins (from 1 to 40 by example, for the largest chips) ?
Did you get the Oric's schematics ?

A+