(but not just yet…)

As sometimes happens, there is a whole lot of nothing… then there is a whole lot of something. Cort (N0MJS) made excellent progress on the front panel. Some images of the progress follow:

The (nuclear bomb) reset switch cover and keypad bezel

Logo and other decals test fitting (trim colors are not final)

The final configuration, with decals and painted panel vs. the ACC original

Personally, I think this panel is AWESOME, even if it isn’t an accurate copy of the original. We are going to punt on the back panel labels & use a label printer as an interim solution. A more permanent solution will (might?) come later…

Lets Get On With It Already!

I decided to set aside a 3-day weekend to solder the RC-96 PCB. This mostly happened – my mobile radio died so I had to spend one of those days installing a replacement. Fortunately, I was mostly done with the RC-96 in only 2 days.

First, I needed a leadforming tool for the AXIAL devices. So, off to the 3D printer we go:

A quick-n-dirty leadforming tool

Next, I needed to prep the PCB. As previously mentioned, I was concerned about tin-lead †”oxidation” that might have occurred since the PCB was fabricated. Most PCB assemblers don’t like to process PCBs that have sat on the shelf in favorable environmental conditions for 6+ months – this one has been kept in unknown conditions for over 30 years. I settled on lemon juice, rubbing both sides of the PCB with half of a lemon followed by a water rinse. The weak acid in the juice would help remove some of the oxide buildup that had accumulated over the last 30 years but would not be so strong that it might significantly eat away at any of the metals or other structures. I could then apply the S.C.A.B.s for the speaker & power jacks.

As noted in a previous post, I couldn’t find leaded substitutes for the power and speaker jacks. There are a lot of connector-compatible surface-mount types available, but these pinouts are not compatible with the RC-96 footprints and their “Z-axis” wouldn’t be right, leaving the center axis of each connector way-off (too low) from the original chassis configuration. For the speaker jack, a two-board, layered approach was needed to get the correct Z-axis result:

The speaker jack S.C.A.B. stack

S.C.A.B. for the power jack

For both S.C.A.B. locations, the RC-96 soldermask was scratched away at strategic locations to provide a solder “pad” to improve the mechanical stability of the structure. The original solder holes were also soldered to the S.C.A.B. to accomplish the electrical connection to the target connector.

Connector test fit

The last prep was to drill 2, 40 mil holes for the phone transformer leads. The holes are situated at the edge of T1 pads located at the upper-right and lower-left in this image:

These holes allow the substitute transformer to fit onto the RC-96 footprint with minimal disturbance to the PCB and transformer.

Johnny Five says “No disassemble!”

The rest of the assembly proceeded without incident. I tend to assemble vertically – I start with the “lower” devices, such as resistors, and then proceed to taller parts as I progress.

Progression of component attachments…

The (nearly finished) “Last” RC-96 shown above the borrowed RC-96

FINALLY… I present: the LAST RC-96, ready for final assembly (inserting the socketed parts) and testing:

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† – The term “oxidation” does not fully encapsulate the electrochemical effects that occur during the aging of a metallic alloy in a given environment, but it is close enough for the purposes of this discussion.