Volvo Penta MD7A / MD7B replacement instrument panel

The original instrument panel for the MD7A(/MD7B is getting old. Mine was breaking apart by itself.

This is an "almost drop in" replacement that reuse some of the old parts from my boat - possibly not possible with someone else's boat, we're talking 45+ years of potentially changing out original details - combined with new parts from "common online sources".

Print it with the front up. 

Since it is a high likelihood that this model only works for me and the parts I managed to get hold of, this is the important design parameters:

• The panel is a 10 mm  thick square slab, 140x140 mm with a 120x120 mm drill pattern for the corner screws.

• There are a number of holes, out of which only the following are "mandatory":

  • A key switch to crank the engine

  • A "charge lamp" that must be a real lamp, unless you have a significantly more modern alternator. The function of the lamp is not only to indicate if charging works or not, but also to energize the windings in the anternator - no lamp means that the charging won't start. 

  • Indicators for low oil pressure and high temperature

• Check what thickness works for the hardware you add to the panel - in my case, the VDO instrument needed thinner plastics to accomodate the length of the clamp. 

As long as this is fulfilled, anything works for the instrument panel. 

I replaced the original alarm buzzer (dead, many years ago) with a cigarette lighter socket for helm charging. The new summer is on the inside - it is noisy enough - and the new warning lights make noise as well. 

I printed the first version in white PLA (runs cooler in the sun than black that tends to melt), one should probably use PETG or ABS instead, or have someone machine it from aluminium or stainless.

Probably not ABYC certifiable, but I do not care - I live in Europe and this is by far not the worst installation in my boat after 40+ years of other owners. 

Installation hints:

• When dismantling the old panel it is critical that you label the cables in a way that you will understand later. Make notes. Take photos.

• Pre-wire as much as possible before installing the new panel, that will greatly simplify things and make it look a lot better once in place - much of the original wiring and most important stacked wire lugs can be replaced by some thinking. 

• Butyl tape is your friend. It also makes things stick very well. 

New parts I used in addition to the print:

• LED rocker switches, Aliexpress. There might be two different versions of these, with the little tab on varying sides (can easily be fixed post print by using a needle file) and slightly different locking mechanisms, but these are the ones I ended up using (affiliate link): https://s.click.aliexpress.com/e/_c3bNHd69

• The lighter plug socket was bought locally, but you can probably use something like this (affiliate link) https://s.click.aliexpress.com/e/_c3MMOn4h , the hole in the print is 30 mm.

• Jeff sold me the two indicator lights with sound for oil and temperature, https://www.amazon.se/-/en/dp/B0B72LX3TY?th=1 . These blink and make noise when activated which I think is a +1 compared to a static light. I haven't managed to find an equivalent at Aliexpress for these. If you do not want the warning buzzer, anything that fits in 19 mm holes are okay. These can be LEDs.

• The charging lamp is also locally sourced, 17 mm hole. Please note - as stated above, this MUST be a real lamp or the charging will not start! For those in Sweden, you can find it here: https://www.mekonomen.se/varningslampa-promeister-10218057

• The unpopulated hole is for a tank indicator light - I'm still considering options here. The hole is 10 mm

Reused:

• VDO instrument

• Key switch