Marine display Böning AHD1015

[2PAC Mafia]

Hi guys,

I´m trying to repair this unit. It´s monitoring marine display and when it switches on it shows only white screen (back light on) but no graphics.

There are some boards inside but I would say there is a problem at embedded computer, which is a iBase IB881-R. I have seen I have 12V power coming into the board but no power output to the LCD. I´ve seen a power line is missing at a regulator 1117 and SMPS inside are not working. This board is obsolete so I´m trying to find it at some store or repair it.
I have a doubt, at manual is speaking about a connector J21 at page 22 from the manual. It´s about PSon signal. I don´t know if that is a switch on signal into the IB881-R, so should I need ground at pin 4 to start the computer?
Can I work with power without heat sink just to follow power lines? It has a big heat sink but at solder side is not possible to work with heat sink.
I leave you the information here:

http://www.restoretronic.com/descargas/Man Boning/IB881-R.jpg
http://www.restoretronic.com/descargas/Man Boning/IB881-R.pdf
http://www.restoretronic.com/descargas/Man Boning/IB88110a.pdf
http://www.restoretronic.com/descargas/Man Boning/AHD_1015TC_MTC_EN.pdf

 

[Tony Stewart]

WHy not just port the software over to a tablet? ok forget that.. But there must a lot of SBC's with similar functions.

 

[dr pepper]

Ps on could be either a command to turn on the supply, or a o/p to say that thesupply is actually on, mete itand see if it changes state when you try to power up the unit, see what happens, if it goes to an ic see if you can get the datasheet for the ic and from you might be able to find out if its a i/p or an o/p.

Dont run without the 'sink, have you seen a intel chip without a sink, kaboom, this might not happen with your circuit, but it certainly isnt adviseable.

 

[Tony Stewart]

of course CPU can explode (tiny but fatal) if thermal runaway rises faster than CPU can respond to shutdown

 

[2PAC Mafia]

Hi,

thanks. I found a shortcircuit in some 4404 mosfet IC between D-S. After removing the processor it disappeared so I´m going to try exchanging the processor.

 

[2PAC Mafia]

Hi,

finally I found, two different failures. Those very low values at capacitors and mosfets were normal due to something coming from the processor...

First problem BIOS battery.
Second problem ON/OFF signal not working from an interface board.

Here you can see a schematic:

http://www.restoretronic.com/descargas/Man boning/Esquema señal ON OFF.jpg

The display has the ON/OFF pushbutton and signal switch to ground when is pressed. This goes to an interface board which has a microcontroller who receive the signal and makes 2 outputs, one for Back light on which needs a constant 5V enable signal and another for a pulse which would switch on the main processor board IB881. I have no pulse coming out from the microcontroller so I have to modify the circuit to create the pulse at T1 drain point for example, which should go to ground.

I´ve been thinking in putting a 5V relay at R2, just when is pressed the pushbutton relay switch a contact a T1 drain to ground. What do you think? It´s the easiest way avoiding to install more transistors, diodes and so on...

 

[Tony Stewart]

if you install a relay, may it be a reed relay and add diode clamp and shielded or twisted pairs to coil to reduce EMI, which is inevitable.
Then you need to debounce if not already and control the duration of the pulse. Finally the contacts must be hermetically sealed or gold plated. (<2A most are)

A one shot is simply a Cap resistor and a Schmitt inverter. The Cap is in series and is small enough to minimize the current to less than 5mA thru the CMOS input to Vdd,Vss rails - protection diodes . The resistor in shunt may be pulled up or down to determine if you need rising or falling edge input trigger. The CMOS input diodes may benefit from a 470R series resistor to limit current, (not certain on transient current limit) then you can choose any value of C to get RC pulse duration with 2/3 threshold for Schmitt trigger approx. The input bias R with 1~10M to ground or Vcc depending on which edge you wish to create a 1 shot from.

Assuming there are no free gates on board, adding one with an ECN using 30AWG magnet wire is pretty easy. 500 parts to choose from in 1 output types **broken link removed**

All boards must have already a Pwr On Rst or POR signal

 

[dr pepper]

Sounds like it'd work, make sure to put a back emf diode across the relay coil so a spike doesnt blow anything else.
Or how about replacing the power switch with a toggle switch.

 

[2PAC Mafia]

Thanks guys,

finally I did the trick with the relay because I have more work waiting so I had to give a solution. I also had to give constant enable 5V power to Back light board because each time I pressed the ON OFF pushbutton it was working opposite, Back light was off when processor started and viceversa... Now installed on board and running!!!