Improving Timex/Sinclair Tape Loading

Discussions about Sinclair ZX80 and ZX81 Hardware
makeit2day
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Re: Improving Timex/Sinclair Tape Loading

Post by makeit2day » Sun Mar 04, 2018 12:52 am

This is the order code for the LM324
Doing a google search with that code gave me this link: http://cpc.farnell.com/texas-instrument ... dp/SC13781
Obviously you received the wrong IC

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1024MAK
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Re: Improving Timex/Sinclair Tape Loading

Post by 1024MAK » Sun Mar 04, 2018 1:20 am

And here is a photo of Lardo Boffin's board (as received from him):
IMG_6568.JPG
Lardo Boffin's board
Anyone spot the problem?

Mark

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1024MAK
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Re: Improving Timex/Sinclair Tape Loading

Post by 1024MAK » Sun Mar 04, 2018 1:23 am

makeit2day wrote:
Sun Mar 04, 2018 12:52 am
This is the order code for the LM324
Doing a google search with that code gave me this link: http://cpc.farnell.com/texas-instrument ... dp/SC13781
Obviously you received the wrong IC
Not my order, but the order that Lardo Boffin placed...

Mark

makeit2day
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Re: Improving Timex/Sinclair Tape Loading

Post by makeit2day » Sun Mar 04, 2018 2:43 am

A CD4001 does not have the same pin layout as the LM324 nor the same function

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1024MAK
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Re: Improving Timex/Sinclair Tape Loading

Post by 1024MAK » Sun Mar 04, 2018 10:23 am

makeit2day wrote:
Sun Mar 04, 2018 2:43 am
A CD4001 does not have the same pin layout as the LM324 nor the same function
Aye. It's a CMOS Logic chip containing four 2-input NOR gates.
IMG_6572.JPG
LM324AN
IMG_6571.JPG
CD4001BE

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Lardo Boffin
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Re: Improving Timex/Sinclair Tape Loading

Post by Lardo Boffin » Sun Mar 04, 2018 10:33 am

So they sent me the wrong chip?

And I was too daft / trusting to realise. Guess I should not be surprised - they missed half of the order the first time round.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

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1024MAK
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Re: Improving Timex/Sinclair Tape Loading

Post by 1024MAK » Sun Mar 04, 2018 10:58 am

Yeah.

It's always a good idea to check an order.

Not that it helps, but to date, I have received various items from various suppliers that were the wrong part, or where a part was missing from the shipment. And it's not just one supplier. CPC, Farnell, Maplin (via mail order) to name a few, have all dropped the ball at least once. All were happy to sort out the mistake :D

The most recent error was a drum of twin Co-ax cable that I did not order, and which they had to send a courier to collect it. The problem appears to be the wrong item gets put in the storage area or bin. Then the order picking person just goes on the suppliers own part number and bin location, and does not check that against the item description or manufacturers part number.

IMG_6514.JPG
Drum of cable

So, yes, check that what you received is in fact what you ordered.

However, sometimes I find it was me that made the mistake. A bit harder now that you can order via clicking on a web page. But when just using order codes, one digit wrong and...

Anyway, I'll desolder the CD4001BE chip later today, then fit a socket, and then put a LM324 chip in it.

Mark

Lardo Boffin
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Re: Improving Timex/Sinclair Tape Loading

Post by Lardo Boffin » Sun Mar 04, 2018 11:14 am

Thanks. I guess this is where lack of experience comes in. I can check resistors ok and capacitors (so long as they are marked) but other suff not so much! Given that all their products say that photos are generic it never crossed my mind that the chip should say LM324 on it. :oops:
Still I will know for next time. :lol:

Thats two for two with failed builds now - this one due to the wrong IC and the ZX81 rebuild due to a dodgy / not quite good enough 6.5 MHz resonator.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
TS 2000
Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

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1024MAK
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Location: Looking forward to summer in Somerset, UK...

Re: Improving Timex/Sinclair Tape Loading

Post by 1024MAK » Sun Mar 04, 2018 8:42 pm

Lardo Boffin wrote:
Sun Mar 04, 2018 11:14 am
Thanks. I guess this is where lack of experience comes in. I can check resistors ok and capacitors (so long as they are marked) but other suff not so much! Given that all their products say that photos are generic it never crossed my mind that the chip should say LM324 on it. :oops:
Still I will know for next time. :lol:

Thats two for two with failed builds now - this one due to the wrong IC and the ZX81 rebuild due to a dodgy / not quite good enough 6.5 MHz resonator.
The fastest way to learn, is to try stuff and if errors are made, to learn from them. In this case, you should not put too much blame on yourself, it's reasonable to expect the supplier to send the IC that you ordered. And at least 99% of the time, they do get it right (well, I order far more than you, and excluding eBay sellers, I can't remember the last time I was sent the wrong chip, it's other things they mess up with my orders).

The resonator issue with your rebuilt ZX81 is again not really your fault. Anyone could have fallen into that trap, including me!

So here are photos of the board after the CD4001BE chip had been removed and a socket fitted. I also wired up the red LED.
IMG_6576.JPG
Top side
IMG_6575.JPG
Track side
IMG_6578.JPG
LED and wiring
I'm not going to have time to do any testing tonight. If I can find time tomorrow, I will do some testing then. If not, it will be later in the week.

Mark

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gammaray
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Re: Improving Timex/Sinclair Tape Loading

Post by gammaray » Sun Mar 04, 2018 9:53 pm

It is ok😀we are all learning
5-TS1000,UK ZX81<-Sheelagh, US ZX81, 2-TS1500/KDLX , 3-TS2040 printer, 2-TS2020 cassette decks, ZXPAND+AY, ZeddyNET, ZXBlast, UDG, ZX8CCB, AERCO, BUILDS/REPAIRS ZX Spectrum, ZX80 Minstrel, ZXMAX48 v1 v2, 2-TS-2068, ROM, 16kRAM

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