MLX-10DP/20L Keypads stop working

[joekro]

Hello,

Hope someone could help me. We have many phones in the last couple of weeks stop working. The keypads seem to stop working. If we disconnect the phones for a few days then plug them back in they seem to work again. any ideas?

Thanks,

Joe

 

[gshaheen]

This was a known defect in certain earlier releases of the phones. There is no way to fix them, except to send them back to Lucent for complete repair. Probably cheaper just to buy used ones off the net.

 

[Guest_imported]

Yes, it is a problem with the flex board inside the phone. They have been a big cause of confusion mostly with the MLX20. Seems that after a while, the current causes the flex board the heat up and open connections. I have replaced MLX-20's from resalers, only to find the problem will rase it's ugly head with the so called reconditioned phone. Paul

 

[joekro]

I purchased several "reconditioned" phones with the same problem. I a bit scared to purchase more. Was the problem ever corrected. (do the newer phones labeled Lucent (not AT&T) on them have a better flexboard?)

Anyway to repair or replace the flexboard?

Thanks

joe

 

[stratagydk]

MLX phones version A/B/C will all have this problem
and you have to replace the Flex Circuit inside.
For example,
MLX-10D is part # 7712D02(X)-YYY where (X) is the version (A,B,C,D,F,G), and YYY is color (003-black, 264-white)

7712D02D's do not have the known problem of going to sleep, but buttons and LED's may still go bad because they also have Flex Circuits, but a better kind.

Phones with version "F" and "G" such as 7712D04F (MLX10DP) are the newest versions and do not have Flex Circuits in them, so do not have that problem

 

[Guest_imported]

I ordered some new Flex Circuits for my sleepy MLX phones. I got them from triad-online.com for $19 each.

I'm not a phone tech or anything, but I thought I would try to replace the circuits myself. I was shocked to find the the flex circuits inside the phones were burned at the connection points. They must have been really hot at one point. I can see how the circuits got hot and failed.

The replacement was pretty easy. The tricky thing was to keep all the keys in place. By the time I got to the 5th phone it took me 8 minutes from open of the phone to finish.

 

[stratagydk]

tvphonebuy -

They're not burned, just oxidized

 

[gregarican]

This is amazing! I thought we were the only ones experiencing this issue.

I inherited a group of older MLX phones with the problem and I tried replacing them with newly-purchased reconditioned phones that would sporadically have similar issues. I was convinced there were some sort of electrical surges that would go through our cable plant and cause the phones to short out. I even went so far as to purchase a couple of APC line guards for a couple of phone lines!

Glad to know now it boils down to $19 circuit boards. This is great info...

 

[insightbill]

Hey, can someone give me some info as to where I purchase the flex circuits? Cant seem to find any for a good price.

 

[longnite36]

I just received an MLX-20L, used, that i bought off of eBay. Some of the buttons on it were not fuctioning at all. I simply took the phone apart, (only recommended if you have a delicate hand and some electronic REPAIR backgroud), and cleaned the Flexboard with alcohol, using a lent free clothe. Phone is working fine.

John

 

[jlshelton]

"Lent-free clothe" only good before Easter!!

I often tear apart the MLX phones because they get full of crud (spilled coffee, etc) and the buttons stick easily. Hardest part for me is re-inserting some of the flex circuit edges into the connectors.

Mike Sandman (sandman.com) also stocks the flex boards.

 

[ken07734]

Question: does the replacement flexiboard stop the heat up problem?, from what I see in my set it only takes a pencil eraser and about 5minutes to fix. does the new flexi provide heat resistance so the oxidizing stops? or is this just to replace it until the next time it heats up?

 

[rkochis]

Is this issue with the MLX10d only that the keys stop working or does the display go dead also?

I have had to replace a number of phones recently that go to blank and will never wake up. Is this a related issue?

Thanks in advance.