Serial com problem on EII

[razo]

I have an EII with serial no. 1180. But the serial communication does not seem to work. I have tried with EmuSer built by Freddy (haven´t tried with old Mac/SoundDesigner, yet) I have read that serial no´s below 990(?) will not communicate via the data serial cable. My question: is there any point to give the EII to my tech to try to fix this?
What can I do to get the data port working?

Dr.C ?

[Wolfram]

Maybe the previous owner change the mainbord. ?

Did you ever measure the signals on the EII serial port?

[razo]

Hi, I don't know the answer to the first question.

I have measured the response on TX+ and TX- on the EII via the testprogram you sendt me when I press EII MacMode using it. I get a response on both TX+ and TX-. TX+ goes from 0V to about 4V in and for TX- from about +4V to 0V when the command is given and toggles back. But, I see that there is about 1V p-p ripple in the "signalstate" (4V) on TX+ and there is an equal constant ripple in the "passivestate" (0V) on TX-.
Aren't these too noisy and what can cause it?

Pressing Exit MacMode in the the testprogram causes it to freeze.
I can upload the pictures of the oscilloscope, if you want.

[dr.c]

Sorry...

Is your machine in RS232 or RS422 ? In other terms, what is the version of your board, and is there a piggyback retrofit on the Main board for RS422 ?

[razo]

Hi,
It has a rev.1 digital board and there is no piggyback retrofit on the Main board (Just the memory piggyback board)

[razo]

What do you think?

[Elmbeatz]

I'm no expert, but I think that later models with a rev1 mainboard have the rs422 by default.

Maybe there's a way for you to try the old mac / sounddesigner route?

[esynthesist]

It seems you can put the EII in Mac Mode (=fast mode at 500kbaud) but you can't bring it back in Midi Mode (=slow mode at 31250 baud) and during fast mode no communication is possible.
The DC levels of the TX pins seem correct. The noise however is pretty high, but I don't know whether that's causing the communication problem.
Perhaps the EII can transmit in fast mode but it can't receive in fast mode.
Is the clock working correctly (pin 9 on the EII should transmit a 500 kHz block signal) ? If the clock signal is not available, no fast communication is possible with the EmuSer.
Another possibility is that the receiver IC is broken.
I don't know what test program Wolfram has sent to you, but if it tries to send at least one command in the fast mode (so after having sent the command instructing the EII to switch to fast mode), you should see a valid signal on the RX pins as well.

On my first Emulator-II the RS422 wasn't working neither. The problem was resolved by replacing the driver IC (transmitter). But the receiver IC is a weak point as well. That Emulator had a piggyback board however.

[Wolfram]

My test program tested is there any respond.
But he said there was nothing shown. So, either the EII sends nothing or there is no clock.
But the EII switched to 500k.

[razo]

The 500Hz clock signal is there. I also checked that all three mofications suggested in the "SoundDesigner troubleshooting"-document have been done. I have ordered new driver ICs today: DS26LS31CN and DS26LS32CN and expect them next week.

[razo]

Update: I installed the two new driver ICs but the EmuSer/OSX connection was still not successful. In the meantime I have got my SE/30 with OS7.1 up and go and EII SoundDesigner had no problem communicating with it - it seems this old technology is more robust than the new one! Now I can have the parameters in the EII updated in realtime from the SE/30 screen

I still think the problem must be the noisy signals I saw on the scope and that it can be fixed - I guess it could be due to bad capacitors and I should recap the whole digitalboard, but I won´t do it yet now that my EII system is working properly for the first time