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Timex Sinclair 1000 repair

Started by JKnightandKARR, Jan 02, 2026, 01:44 PM

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JKnightandKARR

Quote from: granz on Apr 19, 2026, 09:58 PMI don't know - it seems that it would be better to just buy a replacement (https://www.vretrodesign.com/products/vla81-zx81-ula-replacement - and it has 13 5-star reviews) rather than trying to build your own.

Plus it always bothers me when someone produces a document that has a large percentage dedicated to "not my fault" disclaimer legalese.
Haven't found that site at all, I just get the one with no shipping to US available.... besides FleeBay. lol THANKS!

granz

Glad to help. I hope that it helps get your Sinclair working.

JKnightandKARR

Quote from: granz on Apr 19, 2026, 09:58 PMI don't know - it seems that it would be better to just buy a replacement (https://www.vretrodesign.com/products/vla81-zx81-ula-replacement - and it has 13 5-star reviews) rather than trying to build your own.

Plus it always bothers me when someone produces a document that has a large percentage dedicated to "not my fault" disclaimer legalese.
Do me a favor? Can you put in your info in there, like you was buying one, minus payment info, and see if it accepts your address?  It says cannot ship to my address. Wonder if it's a terrif thing??

granz

Yep, I'm getting the same:
QuoteShipping not available
Your order cannot be shipped to the selected address. Review your address to ensure it's correct and try again, or select a different address.

You are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.

Chris Savage

Quote from: granz on Apr 25, 2026, 03:33 PMYou are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.

There are Tindie stores I have previously purchased from that are not shipping to the U.S. currently (some are in the U.K.) because of the tariff issues.

                     Bringing concepts to life through engineering.

JKnightandKARR

Quote from: granz on Apr 25, 2026, 03:33 PMYep, I'm getting the same:
QuoteShipping not available
Your order cannot be shipped to the selected address. Review your address to ensure it's correct and try again, or select a different address.

You are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.
Quote from: Chris Savage on Apr 25, 2026, 09:40 PM
Quote from: granz on Apr 25, 2026, 03:33 PMYou are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.

There are Tindie stores I have previously purchased from that are not shipping to the U.S. currently (some are in the U.K.) because of the tariff issues.

Crap....... was hoping for $35 vs $50......

JKnightandKARR

Quote from: granz on Apr 25, 2026, 03:33 PMYep, I'm getting the same:
QuoteShipping not available
Your order cannot be shipped to the selected address. Review your address to ensure it's correct and try again, or select a different address.

You are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.
Quote from: Chris Savage on Apr 25, 2026, 09:40 PM
Quote from: granz on Apr 25, 2026, 03:33 PMYou are probably correct about it being a tariff issue. Maybe holding off for a while until other countries cut back on their tariffs on U.S. products, and then we can cut back on products from them.

There are Tindie stores I have previously purchased from that are not shipping to the U.S. currently (some are in the U.K.) because of the tariff issues.
Well, I got these 2 items.... more then wanted to pay, but no other options....
https://www.ebay.com/itm/306717973814
https://www.ebay.com/itm/177966875115

Will find one of these to replace the 5v regulator.... the one in there gets REALLY hot, so better be safe than sorry, I'd get it on there but $6.99 + like $8.xx shipping is ridiculous....
https://www.ebay.com/itm/305400148473

granz

I seem to recall that the heat sink on my Sinclair ZX-81 was pretty big, and that it had a "spring" that transferred heat to the metal paint on the inside of the case. Maybe if you put that large of a heat sink on the voltage regulator (7805 IIRC) it will keep it cool enough.

Chris Savage

Quote from: JKnightandKARR on Apr 26, 2026, 12:39 PMWill find one of these to replace the 5v regulator.... the one in there gets REALLY hot, so better be safe than sorry, I'd get it on there but $6.99 + like $8.xx shipping is ridiculous....https://www.ebay.com/itm/305400148473

It's so funny you mentioning the Traco TSR 1-2450. I get mine from Digikey. They're a great replacement for the LM7805, which does dissipate a LOT of heat, since it's a linear regulator. Just be aware that the minimum input voltage is 6.5V@1A.

                     Bringing concepts to life through engineering.

JKnightandKARR

Quote from: granz on Apr 26, 2026, 12:53 PMI seem to recall that the heat sink on my Sinclair ZX-81 was pretty big, and that it had a "spring" that transferred heat to the metal paint on the inside of the case. Maybe if you put that large of a heat sink on the voltage regulator (7805 IIRC) it will keep it cool enough.
Maybe, IDK.... might have large enough heatsinks, even something from an old motherboard.


Quote from: Chris Savage on Apr 26, 2026, 03:30 PM
Quote from: JKnightandKARR on Apr 26, 2026, 12:39 PMWill find one of these to replace the 5v regulator.... the one in there gets REALLY hot, so better be safe than sorry, I'd get it on there but $6.99 + like $8.xx shipping is ridiculous....https://www.ebay.com/itm/305400148473

It's so funny you mentioning the Traco TSR 1-2450. I get mine from Digikey. They're a great replacement for the LM7805, which does dissipate a LOT of heat, since it's a linear regulator. Just be aware that the minimum input voltage is 6.5V@1A.
Wall adapter is 9v@1A, so shouldn't be a problem...  lol

granz

Quote from: JKnightandKARR on Apr 26, 2026, 10:43 PM
Quote from: granz on Apr 26, 2026, 12:53 PMI seem to recall that the heat sink on my Sinclair ZX-81 was pretty big, and that it had a "spring" that transferred heat to the metal paint on the inside of the case. Maybe if you put that large of a heat sink on the voltage regulator (7805 IIRC) it will keep it cool enough.
Maybe, IDK.... might have large enough heatsinks, even something from an old motherboard.
Again, if I remember correctly, the heat sink on my ZX-81 was simply a flat square of aluminum - maybe 2" by 2". That should be simple enough to make, and being flat, it fit inside the case with no trouble.

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