EQMOD schematic error!

[perfrej]

I thought I should get rid of the handset now that I'm running ASCOM with my NEQ6. Checked out the EQMOD site and looked at their schematic, just to see how the DB9 on the NEQ6 is configured.

I immediately spotted an error in the schematic... It is guaranteed to fry your NEQ6 control board!

I am not e member on Yahoo where the discussions take place so I'm posting here instead. I will post a corrected schematic here, and maybe someone with a Yahoo account (don't think I want one for myself) can post it on Yahoo Groups.

I have all the parts required in my leftover drawer so I will build an interface no later than tomorrow and verify everything.

Back shortly...

/per

[Gina]

With such a lot of wrong info about I'm wondering about buying the EQDIR box from FLO at a seeming costly 40 odd quid, for peace of mind. I know that works and will not fry my NEQ6 system

[NickK]

A yahoo account is simple to setup, doesn't require that much info either, nor do you need to enter your own private email address.

[chrisshillito]

I immediately spotted an error in the schematic... It is guaranteed to fry your NEQ6 control board!

Please state which connection(s) you believe to be in error.

Chris.

[cgarry]

It is guaranteed to fry your NEQ6 control board!

Really? In that case I want my money back as mine works fine with no frying.

Chris

[perfrej]

Backing off here!

It turns out that the "error" is Maxim's incredible stupid naming of the pins:

TIN is TTL IN

TOUT is RS232 out

RIN is RS232 IN

ROUT is TTL OUT

How is that for logic???

In my defense, I can add that the capictor values are wrong They should all be 1 uF, not 10 uF as stated in the schematic...

So, sorry for the blown whistle and I stand corrected!

All the best,

Per

[Gina]

No wonder you were misled! Silly people!!

[Psychobilly]

Nowt wrong with that reflects the function of the Chip...

[perfrej]

Psychobilly, I disagree. The logical thing would be:

T1IN -> R1OUT

T2IN -> R2OUT

T1OUT <- R1IN

T2OUT <- R2IN

The way they have done it, T stands for TTL, but only in 50% of the cases... If it were to mean Rx and Tx it would have to imply direction some way and it doesn't.

Just my two rubels worth...

[Psychobilly]

T stands for Transmit R for Receive (RS232 signals) the chip is only providing level conversion from TTL to the "proper" levels for RS-232 signalling so Transmit doesn't suddenly become Recieve...Why should it? Normally TOUT and RIN would be routed to a physicall connector on the product when they would be T(x)OUT and R(x)IN...

Perhaps you should have a word with Maxim for them to adopt your naming scheme

Billy...

[perfrej]

Billy,

Haha, yes, that would be nice, wouldn't it. I still feel that their scheme is confusing, and I know that they mean Tx and Rx, all from the perspective of the RS232 levels being the "true" ones.

Anyway, I have 5V available in my pelican case that contains batteries, USB connectors, camera power and mount connection, so I'll just place my newly built "dongle" in the case and use a straight DB9 cable from it to the mount. I'm using PC-Direct right now, and even though it works flawlessly, I would like to lose the hand controller.

I now have up to early August to tear down the mount, the case and everything and have it all in order when darkness at night returns then.

Cheers!

/p

[chrisshillito]

I still feel that their scheme is confusing, and I know that they mean Tx and Rx, all from the perspective of the RS232 levels being the "true" ones.

To be honest it really doesn't matter if you personally find the naming scheme confusing. The simple fact is you made a mistake, that's OK, we all do it - you really don't have to justify your error by blaming Maxim.

All that really matters now is that folks are reassured that the EQMOD schematic is in fact correct. The fact that folks have been successfully building to this schematic for over 5 years is proof of this.

The whole point of the EQMOD project is that it is free and having put considerable time and effort into this project the last thing I want is folks like Gina feeling driven to buy a commercial product - that really isn't what we're about.

Chris.

[perfrej]

Chris,

Wasn't blaming... I make tons of mistakes and can admit it.