Question about QRX 9001 boards with rivets

[Jefft91]

I'm working on a recently-acquired QRX-9001. The F-2634 4-channel board is a 2-sided board with rivets in the through-hole vias. I thought I'd need to pin these vias, but with the rivets, it seems that isn't necessary. I'm considering just re-soldering to assure there's a good connection to both sides. Anyone out there with experience on this? I'm happy to put in pins. I just don't want to waste time and effort is this is totally unnecessary.

I'll create a post on the restoration when I get some time.

Board with some de-soldered vias:

 

[Sansuiman]

The rivets were the factory attempt to solve the problem of failed vias and resulting signal dropouts. It worked short term, but eventually these failed also from thermal expansion and contraction cycles and slight deflection of the board due to it sitting horizontally, and having the weight of the two plug in boards sitting on top of it.

I repaired a couple of these ~20 years back by removing all the existing solder from the vias with a vacuum desoldering rig and replacing it with modern good quality solder reflowed into the rivets. Both units still work, but if I were doing the job now, I'd pin these to be absolutely sure I'd not need to worry about any further issues.

 

[Jefft91]

Thanks @Sansuiman for the quick response. I'm in the belly of the beast, so I might as well re-pin this and never look back. I'm assuming the same is true for the Dolby board.

[edit] On closer inspection it appears the Dolby board (F2633) is a one-sided board in the QRX-9001.

Regards,
Jeff

 

[KeithD]

Thanks @Sansuiman for the quick response. I'm in the belly of the beast, so I might as well re-pin this and never look back. I'm assuming the same is true for the Dolby board.

[edit] On closer inspection it appears the Dolby board (F2633) is a one-sided board in the QRX-9001.

Regards,
Jeff

Agree, once you are in there, there is no reason not to put pins in. I saved the capacitor leg cut offs from a couple of re-cap jobs, so I had plenty of "pins" to use when I did the board in my 8001.

 

[AE Bob]

I have done many of the QRX-x001 receivers (as well as the x0x0DB units). I do not pin the rivets, and don't see any reason to. The issue is not that the rivet failed in the middle of the board. It is that the rivets are no longer connected to the foils on the top and bottom. Placing a wire through the rivet might improve the connection to the foils if it is bent over and soldered to the foil itself, but is totally redundant if just placed through the rivet. I repair them by removing the existing solder, because it will bubble when reworking the solder connections (apparently flux from the original wave soldering). I then resolder the rivets on both sides, leaving a good thick fillet between the rivet and foil. This prevents the issue from re-occurring as it did with the thin membrane created by the original wave solder connections. I see the rivet issue just like many other solder connection issues where "ring cracks" develop because of the thin wave solder membrane.