ADA Depot Too - A Forum To Support Users of ADA Amplification Gear

Please login or register.

Login with username, password and session length
Advanced search  

News:

Lets get Technical > All Things Tube All about preamp and power amp Tubes.

Pages: [1]   Go Down

Author Topic: MP2 won't get out of standby mode  (Read 2403 times)

0 Members and 1 Guest are viewing this topic.

lesag002

  • Newbie
  • *
  • Offline Offline
  • Posts: 3
MP2 won't get out of standby mode
« on: Time Format »

Ever since I bought my MP2 (early 90's?), it has always remained in standby mode (with the "tubes warming up..." message) when first turned on.  In order to get out of standby, I've always had to turn the power switch off and on again.  It's as if a sensor is not detecting that the tubes are warmed up, so it never switches the unit out of standby.  But when it's turned off and on again, the sensor apparently detects heat and bypasses standby and the unit is then ready to play.  This is the only problem I've ever had with it.  Still kicking myself for not returning it for another unit.  Any fix for this?
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3758
    • marshalljmpmodshop.net
Re: MP2 won't get out of standby mode
« Reply #1 on: Time Format »

There's no heat sensor or anything like that.It actually works with a sort of timer.Usually the problem is U104,that's a 74ls08 ic.Normally when you replace it ,it will sove the problem.It's also cheap around 0.5 to 1 $.If that doesn't help try to replace C104 (33µF/50V).
Logged

lesag002

  • Newbie
  • *
  • Offline Offline
  • Posts: 3
Re: MP2 won't get out of standby mode
« Reply #2 on: Time Format »

Awesome!  Thanks very much!

So, is this IC clearly marked on the pcb?  Is it in a socket so I can easily swap it out?
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3758
    • marshalljmpmodshop.net
Re: MP2 won't get out of standby mode
« Reply #3 on: Time Format »

Normally yes,try to locate it in the schematics pcb.

It's not in a socket so be carefull.

http://tuukan.fliput.net/pcbfix_en.html

Best way if you don't a desoldering  gun is to cut the legs and get them out one by one,see link.
Logged

lesag002

  • Newbie
  • *
  • Offline Offline
  • Posts: 3
Re: MP2 won't get out of standby mode
« Reply #4 on: Time Format »

Thanks again!  I just noticed the eprom is version 1.23.  Any chance upgrading that would fix the issue.  At least that's in a socket ;)

What does ver. 1.41 do?
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3758
    • marshalljmpmodshop.net
Re: MP2 won't get out of standby mode
« Reply #5 on: Time Format »

No that doesn't fix this problem.

Fixed some small bugs but most importent faster switching.
Logged
Pages: [1]   Go Up