Improving Timex/Sinclair Tape Loading

[makeit2day]

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

[1024MAK]

And here is a photo of Lardo Boffin's board (as received from him):

Lardo Boffin's board

Anyone spot the problem?

Mark

[1024MAK]

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]

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

[1024MAK]

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.

LM324AN

CD4001BE

Mark

[Lardo Boffin]

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.

[1024MAK]

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

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.

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]

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.
Still I will know for next time.

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.

[1024MAK]

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.
Still I will know for next time.

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.

Top side

Track side

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

[gammaray]

It is okwe are all learning