Dillen wrote:

Very nice work indeed!

Martin

Martin, when I started the project, I knew exactly what to look for and what to do because most of the information came from the THIS forum.  When starting a project, people should really search and extract every piece of information from this website; it is an endless valuable resource.  And you as a person, really helping DIY’s like me to bringing back to life those old reputable piece of engineering; thank you for that! 🤒

Thanks Graig!

If you ask my wife, yes too much fun doing this hobby, as I'm slowly filling the house with my stuff! 😁 

Thanks Graig!

If you ask my wife, yes too much fun doing this hobby, as I'm slowly filling the house with my stuff! 😁 

Very nice job!

Those M70s are our living room speakers and they sound so nice and unfatiguing.

And they have that prodigious bass too. We use a Beomaster 4400 on linear mode.

Thanks Jacques,

Guess what's on the workbench right now?  And who inspired me the most?  You have a lot to with all this Jacques! 🤒

Just missing the Beogram 4002 but working on it as we speak! 

Were the output trannies fried?

chartz wrote:

Were the output trannies fried?

Hi Jacques, 

0 0 1 147 842 Compass-NAV inc. 7 1 988 14.0 Normal 0 false false false EN-CA JA X-NONE Unfortunately yes, two TIP141 on the right channel that I find very strange by the way, but I think I have pinpointed the problem. You see, I consulted the site many times to find the common anomalies for this amplifier before beginning the restoration of mine. In all cases, some output transistors were defective and that, in my opinion, it's really not normal, because this amp is very well protected at the output stage. I have never seen, in all my restorations, damaged output transistors without any damage in the upstream output circuit either through abuse, "visible" component failure or something else... In my case, everything is good, but two failed TIP141 ... ??? As you know, the number one cause of chip failure is heat.  I very much suspect that the heat dissipation from the back plate, where the trannies are mounted, to the heatsink is very bad because of the modular design. I do not want to dwell on it here, but you can see the details on my post here: /forum/imported-unmapped/bm4400-restoration-in-progress

Rich wrote:

Welly welly welly done! Welcome to the M70 club!

 

 

You seem the perfect person to take on P45s with stuck woofers....😎

Thanks Rich, you've been there right? 😁

No thanks for the P45, I have enough on the workbench right now 😕

Great job!!

Now I have a few questions as I am doing some work on my 70's.

Did you replace the foam on the front of the speaker? Did you epoxy all of the drivers?

It looks like you have to remove the mid range driver from the inside and not touch the nuts you see on the front?

How did you reattach the grills?

Mine sound great now and I want to make sure they do for a long time.

Thanks, Jim.