Sound Skulptor forums

Build help and troubleshooting => MC624 Monitor Controller => Topic started by: Steveng on February 26, 2025, 06:23:16 PM

Title: Remote unit not communicating with MC624
Post by: Steveng on February 26, 2025, 06:23:16 PM

My newly built MC 624 seems to be working well, but when I attempted to connect the Remote unit, it only displays  -63 and lights up the first input and output only, and not responsive to any controls. I put a jumper on +12, since the PC board is V1.4, both microcontroller chips are V1.8.
Suggestions?

Title: Re: Remote unit not communicating with MC624
Post by: JPK on February 27, 2025, 09:52:36 AM

Please give more details:
REM624: does it react to the switches / level ?
MC624: does it work normally when disconnected? Does it switch to -63 immediately when you connect it to the remote.
Are the various voltages correct when the 2 are connected together?

Title: Re: Remote unit not communicating with MC624
Post by: Steveng on February 27, 2025, 04:16:58 PM

The Remote is totally non responsive, the display (-63) comes on immediately and stays, with no correlation with the main unit, and the first input and output light up as well.
The main unit works well, and programs fine, whether it's plugged in to the remote or not.
the V pins are spot on for the 3.3, 5, 16 and -16, but the +12 V pin reads + 6 V.
the TP pins read -5V.

Title: Re: Remote unit not communicating with MC624
Post by: JPK on February 28, 2025, 06:14:39 PM

but the +12 V pin reads + 6 V.
Not normal. 
Is it the same when the remote is disconnected?
Check the external power adapter. It should supply 12V, same as the 12V test pin.
Make sure the remote is in Master mode (press MUTE+DIM).

Title: Re: Remote unit not communicating with MC624
Post by: Steveng on February 28, 2025, 07:16:17 PM

I'm not sure what's different today, but the 12V pin measures 11.25v now- with or without the Rem hooked up, the 12v adapter does read 12 V, the unit has been in Master mode.

Title: Re: Remote unit not communicating with MC624
Post by: JPK on March 01, 2025, 09:15:47 AM

So there is something wrong in the rem unit.
You must check everything:
- IC's position,
- IC's direction,
- Solder joints
- ...

Title: Re: Remote unit not communicating with MC624
Post by: Steveng on March 01, 2025, 11:46:49 PM

I went through the remote unit, and it all looks decent, lifted and reseated the two IC's, double checked the transistors, the solder joints look good, don't feel like reheating the whole board yet, is there not anymore "troubleshooting/testing" that can be done, how do we know that the 20' usb cable is passing anything more than just power?

Title: Re: Remote unit not communicating with MC624
Post by: JPK on March 02, 2025, 09:02:43 AM

Check the supply voltages on the remote:
+5V on U5 and U6, between the pins 1 and 16.
+3.3V on U3, between the pins 20 and 19.

The signal sent to the MC624 can be seen accross R5.
Could you post some pictures of the boards?

Title: Re: Remote unit not communicating with MC624
Post by: Steveng on March 02, 2025, 11:28:43 PM

The voltages are right on, (not sure what you mean about the signal being seen across R5),
I will reflow  some joints and see, and get back some pics to you if nothing changes.

Title: Re: Remote unit not communicating with MC624
Post by: Steveng on March 04, 2025, 01:26:58 AM

I decided to reflow the entire remote unit just in case, but alas, no change.
Maybe you could explain how to check the signal across R 5, please.
Not sure how to send pics in this forum, don't understand the Url setup.
(I guess I'll have to email them directly to JPK/SS)