hi guys, I have bought a loose Oric-1 a few weeks ago for only 50.00 € , and since I had some free time today, I wanted to give it a quick look. Here is the beast, nothing fancy, just the usual Oric-1, no PSU, no video cable. I have a multiple voltage center positive PSU, but I have no video cable (and no TV set that accepts the RF signal), I just wanted to PING, ZAP, SHOOT and EXPLODE it before I build (or buy, I don't know yet) an RGB SCART cable. I first did a little mistake, by applying 15V (instead of the 9V required) for a couple of seconds before I see my error. Since the voltage is regulated by a 7905 + radiator, and since no magic smoke or poping noise came from the Oric, I thought my error was not a big deal. I then applied +9V and blindly typed "ZAP" followed by ENTER several times, but the Oric remained silent. Now I just can hear a scratching sound when I plug in the PSU (not concerning), and a constant faint humming sound from the speaker... My first thought was: the 7905 is fried. I decided to have a look inside. The inside is clean, with no signs of rust or oxydation, nothing special to report. I have discovered an issue 3 motherboard. Notice the IC10 & IC11 are not present. Most of the chips were manufactured in 1983 at the exception of the sound chip from 1982. This one was changed at some point, I can clearly see some rework was done on its solder joints. The main board, issue 3 mfd. in 1983 excepted IC4 replaced by a 1982 chip version. I have desoldered the 7905. I have measured the output voltage from the 7905 and it gave me... +3.8V Isn't it supposed to be -5V? I measured some various points on the motherboard and still, 3.8V, and some points at +8.8V are we supposed to find some 9V on the board? Or thinking of it, it is just because I measured the voltage before the 7905(?)... I have desoldered the 7905 to test it apart from the board, it is not shorted. With my bench power supply it still gives +3.9V instead of the usual -5V. I already have ordered a new 7905. What do you think? Is there something else I should do? If I would like to power the Oric with my bench power supply, how should I plug it? The 7905 puzzles me, I am more used to deal with positive voltage 7805s. I found that the 7905 leftmost pin (IN) is considered as the + line, whereas the center (GND) and rightmost (OUT) are considered as Ground? Can I safely power +5V to the leftmost and GND to the rightmost pin holes? Let me know, skilled Oricians!!