Search found 7 matches

by RetroTechie
Mon Jul 29, 2019 10:52 pm
Forum: Technical questions
Topic: Telestrat failure?
Replies: 22
Views: 1842

Re: Telestrat failure?

... ever trod on a DIP IC? Barefoot? PROUD to say that once, I have, and barefoot indeed! :lol: Iirc a small DIP like TL072 opamp or such. Pins upwards ofcourse thx to Murphy. I discovered a brand of a/s foam that turned to mush with age. Learned that as well not too long ago. Not due to using such...
by RetroTechie
Wed Jun 19, 2019 11:55 pm
Forum: Technical questions
Topic: Telestrat failure?
Replies: 22
Views: 1842

Re: Telestrat failure?

The same applies for OTP (One Time Programmable) chips where you program them, once, by blowing fuses away. In the case of memory, such fuse-programmable chips are normally referred to as PROM. Such as the TBP24S10 used in the Oric's video circuit. PAL programmable logic is also fuse-based. Rarely ...
by RetroTechie
Wed Jun 19, 2019 2:04 am
Forum: Technical questions
Topic: Telestrat failure?
Replies: 22
Views: 1842

Re: Telestrat failure?

Additionally there is no clearly stated info how long is the data retention time of these chips - different sources claim 10-20-40 years (and even >200 years but for EEPROM's). Most accurate estimate: "decades". I have some datasheets for UV EPROMs that state 10-year data retention. I think that's ...
by RetroTechie
Wed Jun 05, 2019 2:45 pm
Forum: Hardware hacks and extensions
Topic: Composite video mod?
Replies: 12
Views: 896

Re: Composite video mod?

Yes if you want better quality RGB -> composite video then AD724 or similar IC is the way to go. I just wanted a cheap / easy 'fall-back' option that used hardware already in the Oric as much as possible. As I understand the Oric schematic, its composite generation is some interplay between the ULA'...
by RetroTechie
Mon Jun 03, 2019 12:08 am
Forum: Hardware hacks and extensions
Topic: Composite video mod?
Replies: 12
Views: 896

Re: Composite video mod?

Okay... can do... drew up a nice schematic: Composite video for the Oric.png R16..R19 are on the Oric mainboard (no changes there), R15 is replaced by this mod. RV1 is removed, the other components are added. RCA socket is the one from the RF can. About the weak composite signal going into the RF mo...
by RetroTechie
Sat Jun 01, 2019 6:50 pm
Forum: Hardware hacks and extensions
Topic: Composite video mod?
Replies: 12
Views: 896

Re: Composite video mod?

Yes I use the RGB output too. But I prefer to have options. Not every TV/monitor takes analog RGB at the horizontal sync frequencies used by home computers like the Oric. And hey the UHF can (read: its RCA connector :wink: ) is there, why not use it? UHF is worthless anyway these days. Never mind th...
by RetroTechie
Sat Jun 01, 2019 6:10 pm
Forum: Hardware hacks and extensions
Topic: Composite video mod?
Replies: 12
Views: 896

Composite video mod?

Hello all! :D I'm new here. Recently I repaired an Oric Atmos that basically sat in a box for many years. Bought it once as "working", which turned out to be not the case, and since I didn't have spare parts like CPU, VIA, ULA etc it got boxed up. Years later I acquired some parts but was busy with ...