[DaveR]

Part 2 Making Reinforcing plate / Modification Of Top Cover


(See Part 1 here:
Pentax K1 Top Cover Reinforcement Procedeure - Part 1 - PentaxForums.com)


Using the old top cover as a template:
Remove/ cut off / scrape off the PCB locating pin (shown with screwdriver).





Cut out a piece of aluminium 17 x 23mm and then cut it finish it with a file in a trapezium shape (21mm opposite the 23mm side) and notch out 1 corner. I used a piece of paper pressed into the top cover with a sharp lead pencil pressing into the corners to make a template that I transferred to the aluminium.


Hold the plate under the top cover while drilling down through the top cover with the 1.6mm drill for each of the 4 screw holes (I used an appropriately sized piece of timber in a vice under the plate and top cover).

Coat the top side of the plate with a marker and scribe around the bigger hole of the top cover to obtain an outline of the hole required for the hotshoe terminal block

(This plate is a first attempt and wasn’t quite right).











Drill and file the hole and make sure all of the holes line up with screws etc. Do a dummy fit up with the hotshoe and terminal block. When everything fits properly dismantle.

(I used “Blu Tack” during a trial run to make sure there was enough clearance with the plate fitted).











Terminal Block Pins

These need to be made longer due to the thickness of the aluminium reinforcing plate. I used 2 methods – each is a little tricky.
1- Solder solid copper wires to the pins
2– Add solder ‘strings’ to the pins











Assembly Of Hotshoe

Have the Loctite applied to the 4 hotshoe screws and silicon sealer ready plus appropriate screwdrivers.




Using a very small screwdriver or similar, apply a small bead of silicon to the mating face of the terminal block and fit it to the top cover (this replaces the white sealant removed when dismantling).











Apply some superglue to the top cover especially in the corners to the left and right of the hotshoe recess. This is not so much to bond the metal hotshoe, but more to take up the tiny spaces underneath it.
(Edit: I think I also applied a little superglue under aluminium reinforcing plate for the same reason)









Fit the hotshoe, the aluminium reinforcing plate, the copper earth plate and the 4,5mm screws before the superglue dries, checking everything is where it should be and any excess glue wiped off.







Fit the PCB over the hotshoe pins and apply pressure to it with a screwdriver etc. whilst soldering the PCB(I fitted an older flash to the hotshoe to make sure there wasn’t any pressure forcing the pins out whilst soldering).











This can actually be the hardest part of the whole process to get right and may take several go’s at each pin without getting each one too hot and melting and distorting the terminal block, but getting the solder hot enough to melt onto the pin which is now just below the surface of the PCB. And / or it may mean putting a piece of wire down through the holes in the PCB to get a good solder joint. Take your time.

Use a multi meter on the PCB and the terminal pin on top to check each solder joint is OK.


IN HINDSIGHT,I would solder 4 insulated wires to the terminal block pins, feeding them forward between the PCB and the copper earth plate, looping them back over the PCB (as there’s plenty of room) and soldering them to the PCB similar to the audio wires attaching to the main camera PCB. This should be a lot easier to make good soldered electrical connections.


After soldering, I applied a tiny amount of superglue around the edges of each of the 4 terminals on the top side of the hotshoe to make sure they were sealed.




The flexible PCB needs to be slightly bent so it will line up with the locating pins near the GPS switch and it functions properly – if you don’t, the switch will be slightly skewed and won’t function properly. Some new or more double sided sticky tape may be needed to hold the PCB in place on the GPS switch plate.




Refit the 3 screws for the GPS switch plate.


















Refitting The Top Cover

Solder all of the top cover wires to the body assembly

Refit the wiring harness to the terminal plug on the body.

Remove the temporary ‘bridge’ at the end of the new on / off switch brush and be careful not to bend the brush during reassembly.

Remove the clear protective plastic from under the LCD cover and make sure there is no dust or loose debris under the cover or on the main camera body etc.

Fold forward slightly the portion of the top cover PCB that you removed the adhesive from when removing the hotshoe, otherwise it will foul on reassembly.






Check all adhesive tape is in place and all wires are attached and not caught up and fit the top cover making sure it fits down as it should. This may take a few go’s and require a little pressure as things have been disturbed and there is now slightly less room above the viewfinder mechanism, but all should fit snuggly.

Replace all screws as per removal of the top cover taking note of the “O” ring behind the viewfinder adjustment dial, and test everything works.

Don’t panic if it doesn’t, just remove the top cover and retrace your steps.



It all looks complicated and scary under there, but each item and step is just that – one at a time.

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Last edited by DaveR; 01-16-2023 at 04:50 PM. Reason: Additional step added (denoted as "Edit:" and minor typos corrected.

[Lord Lucan]

I do a lot of events etc. with flashes on top most of the time and the top covers develop cracks under the hot shoes as there is very little strength in the plastic. It is definitely a weak point as there is no metal in the vicinity, just 5 holes through the plastic of the topcover that eventually crack.

Fascinating and useful stuff. The quote above is from Part 1. Although I have never had a camera top break I am very careful (I don't do events) and for years I have usually used a hammerhead flash which avoids the problem. It is ironic that hammerheads have gone out of fashion just as camera hotshoes have become weaker because of having to accommodate stuff like pop-up flash, WiFi, and GPS (which need plastic surrounds).

PS : Some of the picture links in Part II don't work.

[DaveR]

Lord Lucan, I suspect I use my K1's for more than the designers primarily intended by using them for events. I do use them for all sorts of other stuff like landscapes etc. I don't abuse my gear, and I look after and maintain them well, but I use them as tools and don't baby them. I agree with you regarding the need to accommodate extra features - all while keeping weight down.


I realised years ago (speaking in generalisations) that as photographers we want the best gear that will give us great results, in all sorts of situations, cover all manner of focal lengths, be full of features, be reliable, be easy to use, compact, ergonomic, lightweight and not cost too much! All sorts of design demands!


When you say some of the picture links in Part II don't work, how so? I just tried "Copy image link" on all of them while I was logged out and had no trouble copying and pasting into my browser.

[MarkJerling]

Wow, fantastic work Dave. As one who's flash mount came adrift I admire your dedication to find a (better) solution than the original

[JensE]

Thanks for the very thorough documentation!

Remembering my work on a K50, I'll refrain from performing the surgery and will just continue to use a trigger in the hotshoe and the flash on a bracket, even though that's slightly bulkier. I did not have any trouble with the hot shoe but it still felt too weak to hold a big flash - happy to not have tried 'long enough'.

[MarkJerling]

A question @DaveR
Do you think it will work to simply replace the copper earth plate with a stainless steel plate, to your aluminium plate's dimensions, thereby effecting a reinforcing plate of not much more thickness than the original?

[DaveR]

Mark the copper earthing plate is very thin, I think 0.25mm from memory, it is basically a square and does not cover the whole underside of the area underneath the hotshoe. So, just replacing that 'plate' would be better than original, but I don't think it would be as robust as what I did. You would also need to attach the earth wire to the plate somehow.

Some of my thinking behind my solution:
Aluminium is light and easily machined, is not magnetic and has some flexibility.
Having a plate that closely matches the underside flat area under the hotshoe would allow the transference of forces / movement to the vertical and sloping surfaces of the top cover which would be more rigid (I think I also added superglue under the aluminium plate to take up any space and increase rigidity).
There is enough room for a plate of this thickness (1.5mm) under this area - including near the cut out in the PCB forward of the hotshoe pins / soldered connection (this is where the space is smallest).

Having done it twice, I can now see that it can be a relatively straight forward procedure, especially if wires were soldered to the hotshoe terminal block pins and looped around to the PCB. If someone had a machine shop produce a number of aluminium reinforcing plates using CNC machines / laser cutting and a supply of screws and wires, a number of top covers could be done in a day ready for swapping.

[MarkJerling]

OK, thanks for the explanation. What would be super cool would be to 3D print a titanium top cover, matching the plastic cover in every way. But, cost would be prohibitive. The last time I got a quote for 3D printed metal, it was pretty expensive. (They charge per cubic mm) So, something like this would be about $800 - $1,200, not counting the 3D modeling work.

Yes, yes, I know it's not practical!