Henrique Jorge
Paul LavelleBack in the saddle! Finished up the last part of my Timex Sinclair 1000 restoration project. The last phase is a memory upgrade from 2K to 16K. First, I popped off the existing chip to make way for the upgrade.
AnnieNext week starts like two weeks off from school. Got a migration from Ubuntu 22.04 to Debian 12 planned, and digging out an old tape recorder I have to try to get it working alongside my #TS1000.
Might order a couple connectors so I can get around to building an adapter so I can hook up the FB100 to my #Model100 for some disk storage.
Might order a couple connectors so I can get around to building an adapter so I can hook up the FB100 to my #Model100 for some disk storage.
In the meantime the 7805 on the #ts1000 has some notcua thermal paste I had from my last desktop build between it and the heat sink to ensure better thermal transfer. I just don't know if that's more preventative measure or buying a little more time, given it got hit with significanly more power than it was supposed to be hit with.
Hmm.
Some quick math, it looks like the 7805 in my #TS1000 was hit with enough excess power to send its temps crazy high, assuming the system drew the full 650mw the included power supply could deliver and assuming no heat sink. It did have a heat sink, but no thermal compound so I'm not sure how effective it was. Screw even slightly looser than ideal could have made it effectively uncooled.
Anyone know the actual power draw of one of these systems so I can work out my worst case temps it might have hit a bit more precisely? I doubt it was the full 650(it probably has this power supply because sinclair got a good deal on a large batch of them or already had them in their system for other devices- this is a built to a price point design for sure and would be unlikely to have had a supply built specifically for it or selected to be a close match if they got a good deal on something that was actually overkill),
Basically trying to figure out if it's worth replacing the regulator. It's a 7805 in an easily accessed location so it won't be hard or expensive to replace,so I'll probably swap it if there's even a tiny amount of doubt about whether it lost some lifespan to the failed power supply, but doing actual diagnosis and analysis of what it went through is a learning project.
Looking at this 7805 and what might have happened to it, if I add one to my #RC2014 I think I'll try to find a heat sink I can fit into that space. They can take 12v or even more and output a stable 5, but you can easily burn them up. I don't want that to happen, because incidents I've had with voltage regulators they can fail high and that could mean a dead computer.
#retrocomputing
Some quick math, it looks like the 7805 in my #TS1000 was hit with enough excess power to send its temps crazy high, assuming the system drew the full 650mw the included power supply could deliver and assuming no heat sink. It did have a heat sink, but no thermal compound so I'm not sure how effective it was. Screw even slightly looser than ideal could have made it effectively uncooled.
Anyone know the actual power draw of one of these systems so I can work out my worst case temps it might have hit a bit more precisely? I doubt it was the full 650(it probably has this power supply because sinclair got a good deal on a large batch of them or already had them in their system for other devices- this is a built to a price point design for sure and would be unlikely to have had a supply built specifically for it or selected to be a close match if they got a good deal on something that was actually overkill),
Basically trying to figure out if it's worth replacing the regulator. It's a 7805 in an easily accessed location so it won't be hard or expensive to replace,so I'll probably swap it if there's even a tiny amount of doubt about whether it lost some lifespan to the failed power supply, but doing actual diagnosis and analysis of what it went through is a learning project.
Looking at this 7805 and what might have happened to it, if I add one to my #RC2014 I think I'll try to find a heat sink I can fit into that space. They can take 12v or even more and output a stable 5, but you can easily burn them up. I don't want that to happen, because incidents I've had with voltage regulators they can fail high and that could mean a dead computer.
#retrocomputing
Mark Gardner
Did some research on the TS1000's composite video issue - discovered that some composite mods will overdrive the output a bit, causing the washed out image.
The solution was to drop an additional resistor in-line between the composite mod board and the RCA jack. I used a 47Ω resistor since that was a value I had handy, and it worked!
More progress on the TS1000 tonight - got the composite mod wired in and tested. It worked, but I was disappointed with the amount of noise in the video.
Went ahead with a recap and voltage regulator replacement as planned, and threw some heat sinks on the ULA for good measure. Doing so helped, although video was still really washed out.
haitchfiveEverybody knows that I'm a Speccyhead, but I would totally consider having a Mech-ZX81 or TS1000 in a box like this.
https://www.printables.com/model/439773-mechzx8138-case
