Tascam 58. No sound from channels 1 and 2? Help

[immana]

Hi. Powered up my 58 and all is good except no audio from channels 1 and 2. Meters are bouncing but no sound in sync or repro mode. Tried both XLR and RCA outputs. Cables are good, work in other channels.

I swapped the sounds cards and channel 1 and 2 sound cards work in other channels. The "good" sound cards from working channels do not work in channels 1 and 2. Visual inspection of PCB boards look good.

Any suggestions? Would love to get this running again. Thanks!

 

[fiddler2007]

Could be it's the connectors on the main PCB - channel PCB; a Tascam experienced technician exchanged all and the ones on my channel cards a good few years back, preventive and on his advice as he mentioned the old ones were probably of a lesser quality. I never had problems since that was done anyway -f

 

[SkywaveTDR]

The DIP relays used in these units were a problem for a number of years. They were made by Omron but the ones I have found to replace them are Coto brand. To make things easier for my clients I have been mounting the new ones in sockets. If the relay goes bad just pop the bad one out and put in a new one. Pretty fast repair for maximum up time. Typically the reason for their failure is not the contacts but the opening of the coils. They are at pins 2 and 6 and should measure 1100 to 1400 ohms. A defective coil is one that measures open or in meg ohms. You do not need to take the relay out to test it. he relays were used in RCA and XLR circuits for mute control.

 

[Redandrew]

On my 58 the symptom was intermittent recording and erratic behavior in both the sync and playback functions on the individual channels.

Following this thread and after a thorough diagnostic, I have focused on the motherboard, aiming to narrow down the issue to two main possible causes:

• The Omron relays on the main PCB
• Bad solder joints on the connector board

Now, my question is: how did you dismantle the main PCB with all those cables around?
Is there an easier way to remove it by first detaching some other components?

All the screws have been taken off already, and the cables unplugged but it seems impossible to remove the board from here without further work on the spaghetti cabling.

Of course, the eight individual channel recording/amplifier boards, including the Master Oscillator, have already been safely removed.

Thanks in advance <3
Wish me luck!

Regards
Andrea