TCD-D7 display is dead - UK Vintage Radio Repair and Restoration Discussion Forum

JohnnyPizzut · 7th Jan 2026, 9:01 am

My TCD-D7 was operating but needed cleaning and oiling, so I took it apart after watching all the vids, cleaned and oiled the mechanism.

I got it all back together but the display is dead, and nothing happens.

The backlight was working before disassembly, but that no longer works.

Using a scope, I probed the ribbon cable connector on the main board and see there is 5.2v, but I can't find ANY voltage on the system control board (control panel pcb).

The two crystals connected to IC801 are not running, evidence of no power.

Unfortunately, the terminations of the ribbon cable on the control panel pcb are hidden under the pcb.

Did SONY ever publish the layout of the system control board? I want to "buzz out" the ribbon cable and try to find out what happened to the supply voltage.

JohnnyPizzut · 9th Jan 2026, 9:31 am

Well, I found I misinstalled the securing clip on the control panel ribbon cable.

The clip should go under the ribbon cable, so the wedge forces the contacts on the ribbon against the contacts inside the connector.

But, I don't know if I timed it correctly when I put the mechanism back together.

I'll update the thread after I get it buttoned up and test it.

JohnnyPizzut · 9th Jan 2026, 8:58 pm

It's alive but a tape won't load. I hear gears slipping. Must have screwed up the timing.

It doesn't load, but makes sounds of gears slipping.

I'm taking it back apart, and plan on re-watching a few repair vids, to see where I went wrong.

If anyone has a procedure to do this, I'd appreciate it.

It's alive again, but I hear gears slipping when I try to load a tape.

Going to watch the repair vids again.

Am I correct there are three gears that must be preset before reassembly?

One is the large "sector" gear that loads and unloads the tape, then a top cam gear and a bottom cam gear.

The position of the top cam gear is shown at 14:45 in this video
The bottom cam and sector gears are shown at 15:37:
https://www.youtube.com/watch?v=BPsWIQVf_8c&t=187s

It's a lot of work assembling and disassembling, so I ask if the gears in the attached photos look to be in the correct position?

7th Jan 2026, 9:01 am	#1
JohnnyPizzut Diode Join Date: Jan 2026 Location: Garden Grove, California, USA. Posts: 3	TCD-D7 display is dead My TCD-D7 was operating but needed cleaning and oiling, so I took it apart after watching all the vids, cleaned and oiled the mechanism. I got it all back together but the display is dead, and nothing happens. The backlight was working before disassembly, but that no longer works. Using a scope, I probed the ribbon cable connector on the main board and see there is 5.2v, but I can't find ANY voltage on the system control board (control panel pcb). The two crystals connected to IC801 are not running, evidence of no power. Unfortunately, the terminations of the ribbon cable on the control panel pcb are hidden under the pcb. Did SONY ever publish the layout of the system control board? I want to "buzz out" the ribbon cable and try to find out what happened to the supply voltage.

9th Jan 2026, 9:31 am	#2
JohnnyPizzut Diode Join Date: Jan 2026 Location: Garden Grove, California, USA. Posts: 3	Re: TCD-D7 display is dead Well, I found I misinstalled the securing clip on the control panel ribbon cable. The clip should go under the ribbon cable, so the wedge forces the contacts on the ribbon against the contacts inside the connector. But, I don't know if I timed it correctly when I put the mechanism back together. I'll update the thread after I get it buttoned up and test it.

9th Jan 2026, 8:58 pm	#3
JohnnyPizzut Diode Join Date: Jan 2026 Location: Garden Grove, California, USA. Posts: 3	Re: TCD-D7 display is dead. It's alive but a tape won't load. I hear gears slipping. Must have screwed up the timing. It doesn't load, but makes sounds of gears slipping. I'm taking it back apart, and plan on re-watching a few repair vids, to see where I went wrong. If anyone has a procedure to do this, I'd appreciate it. It's alive again, but I hear gears slipping when I try to load a tape. Going to watch the repair vids again. Am I correct there are three gears that must be preset before reassembly? One is the large "sector" gear that loads and unloads the tape, then a top cam gear and a bottom cam gear. The position of the top cam gear is shown at 14:45 in this video The bottom cam and sector gears are shown at 15:37: https://www.youtube.com/watch?v=BPsWIQVf_8c&t=187s It's a lot of work assembling and disassembling, so I ask if the gears in the attached photos look to be in the correct position? Attached Thumbnails