Hi all

Reading through several other threads on the forum, my first question has been answered - is this a common problem - the answer - YES.

I have had three or four stored for years (in their boxes) that I obtained second hand many years ago. When getting them out their boxes and looking at them the bases of all of them have warped, making them useless on the two middle buttons.

So now do I buy new 7072s or what do other people use instead with better(?) results?

Mike

Hi Mike, I wondered where you might have had them stored? Possibly dampness caused this problem?
I have had most of mine from 60s to early 70s and no problems. Then in the mid 70s to mid 80s they
were in storage during my "sowing my wild oats years". Anyway, M now makes 70729 (page 290 of
new catalog). It uses the old plugs too. I have also found some on ebay. Hope this helps.
Peter

My ones warped in the garage layout from the heat coming through the roof.
I use my own switches from the electrical shop now, using a peg-board to hold them.

Regards,
John

Hi Brandon

I've looked at 7272 boxes and I like the looks of them. I don't think they'll look out of place on my control panel.

Oh well back to ebay.de.

Mike

Hi Ian

The control panels will each be attached to the rear of each large module.

They will consist of several 7072s as well as 7211 and 7070s. There will also be 3 x 30va trafo and one 10va trafo on each panel as well as a 6611 for each module as well.

These will be detachable for storage etc and will mean the the control panels can be stored dry and warm.

I think I should have enough power feeding it with that lot.

Mike

Hi Dan

Thanks

Nice tip - I will try it and let you know.

Text on its way

Mike

Hi all,

After a couple months of accumulating, I started testing. I found some of my 7072s were warped so bad that the center buttons did not work. My brother had good luck dunking a warped Bahia box in hot water and carefully bending it back to where it would stick properly in the cradle again. I used a heat gun on the 7072s. Sometimes they are cheap on Ebay but the current batch on offer aren't and I want them ready for some temporary layout building for this holiday weekend anyway. I used the heat gun on low setting to heat the whole box bottom and especially the center. Then I pressed the box flat to get rid of the overall twist and pressed down inside the center on the brass with a screwdriver to flatten everything. Might help to prop one end up on a small piece of wood to allow the center to push a little below flat. Might need a couple of tries. The top can be done the same way but needs to just be untwisted. Avoid pressing down in the center as you might mess up the overall alignment of the buttons and they won't toggle and pop the way they should. Don't overheat. It seems the plastic wants to contract and shrink when heated. Overheating is probably what warped these in the first place. There were a couple that I had to use a round file to open up the button holes to get them to move freely again.

Opening the box, removing the buttons, closing up and heating the whole thing to twist back into shape did not work too well. The top shrank and needed a whole lot more attention later. I also seemed to get better as I went. Three of five are nearly as good as new (which was never all that great anyway), one is passable and the other is a bit iffy still for the center buttons. Back to shopping for a couple more.

Mike

Interesting with the heat gun experiment. Sometimes I have thought of leaving things in a sunny window to try and slowly work them back into shape...

Luckily I haven't had bad warping on 7072 units, but sometimes they need to be disassembled and worked on. While it adds to cost, I find that the newer style with the rectangular buttons (Marklin #7272, accepts the "old" style sockets, unlike some newer control boxes) are much more reliable, and also easier for children to operate if that is a concern to you.

-Brandon

Have several warped 7072's from my earlier days as a kid in the 60-70's... Don't have the heart to throw them away though....