Don't run the thing for too long without a case on, or the airflow from the fan won't reach the ceramic hybrids, they will overheat, expand, contract, and the solder joints of the relays will crack. Ask me how I know... Btw, try to run the Signal Path Calibration. If it succeeds, it will compensate and calibrate all channels (e.g., weird offsets, tiny differences in amplitude, etc.) and confirm the scope signal path is 100% working. If SPC fails, there may be some lingering problem in the hybrids (or somewhere else on the bottom board) and a reflow of the solder joints goes a long way. Also, there are scripts that you can put on a floppy to hack it with all options, but it seems you already have most of them. Nice donation though, particularly because the most expensive part is the 4 probes...
14:56 _"One day I should make an autopsy of some optocoupler too"_ Yes please. I searched your videos and it doesn't look like you've done one. It would be interesting to see a comparison between cheap and quality ones.
These Dallas chips was commonly used as integrated RTC chips for (mailny cheap variants....) AT PC's clones, from 286 era, up to end of 486 era - later Pentium mainboards had in general RTC constructed in other way, and utilized in 90% of PC's much more modern chip, and CR2032 coincell baterry as a backup.... And yes - these Dallas abominations, had INTEGRATED coincell battery inside (technically this is not even a IC, this is PCB with battery, chip, some passives, melted in black resin/plastic...). Nowadays practically every of that Dallases are flat... Some devices, refuses to boot when this RTC battery inside is flat, and spares for this Dallas is nowadays very weak available - and nobody knows how long will work, because these coincells have some lifespan, even not in use. Fortunatelly, there is some modern projects, to replace this with chip + battery holder. There is possible too, to drill a hole in this (yes!), and solder wires for "external power", but.. this is a litte bit "ghetto mod" ;) Greetings from Poland.
I am the guy who is screaming about your soviet era nuclear plant soldering iron😂 . I like your videos mr wild diode, also your crazy soldering iron. Say hi to your lovely cat....
11:08 i used to explore faulty driver for 22W philips industrial LED lamp, it has non-sync buck topology (w\o pfc) with UF54xx diode, and the fault reason was overheating of this diode lead to bloating of output electrolytic cap and bloody roasted to black pcb, so diode in 150W driver may cause quick house-burning event) its seems to be exactly conduction losses, coz mosfet body diode has even worse reverse-recovery time than diodes in continuous current mode. its also kinda funny that driver design has temperature-protecting circuitry but it was omitted)
Fnirsi требует сохранения настроек. FDD 3.5" проверили?. Лучше снимки экрана использовать. Тёмное стекло вместо фильтра. Может проще LCD монитор встроить?.
Great work, well done. Although it is a shame to now be just black and white, that shutter took so much light I'd just bin it and move on. If it was me I'd get some clear acrylic sheet and cut a piece to stick inside the front bezel and just leave it at that.
There are two type of videos you need to do. One is an SMD soldering tutorial with a gun soldering iron. The other is some political discussion about the current issues in Europe.
Ďakujem za ďalší diel z tejto zaujímavej série, kľudne v nej môžeš pokračovať a rád sa pozriem aj na ďalšie diely, ak ich natočíš. Ale pekne si ten osciloskop dal dohromady, teraz ti môže pekne slúžiť a štvorkanálový digitálny osciloskop, to je aj dnes dosť drahá záležitosť a takto si aspoň získal pekný kúsok do dielne.
Hi Daniel, you're making great progress on this restoration. Nice to watch it, many thanks for posting. If you're interested to read of a previous restoration of the LCD shutter, just search for "TDS 744A colour shutter - TekScopes". This will take you to the TekScopes topic: a replacement (cheaper) can be fitted if necessary. You can also follow the link under "JOSE V. GAVILA". Good luck! Kind regards.
You could check if there is possible to find a composite video signal along with chroma and luma, maybe with that You can generate video signal for external monitor. at that moment there is unclear if color generator circuit is working
ЖК кристаллы возможно уже просто потекли со временем. Так что эта штука в любом случае под замену. Были у меня часы старые с ЖК экраном - так вот, он так потёк, что полностью перестал работать. Клей в старых ЖК экранах со временем разложился и всё. Кина не будет.
RU-vidr Necroware did a great video on reworking those old RTC modules - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ecTZtZhE9bI.html He removes the chip and soldered in cell and crystal and replaces them with a battery socket. Also a good idea to solder a socket into the board while you're at it.
