1998 Mach Stereo Display & Illumination

[Mountaineer302]

Our recently acquired 1998 Mountaineer had the ever so common blank display issue. I resolved thet issue with a Dorman replacement power board. There is however an intermittent problem with the illumination or backlight of the buttons. Also it appears that 2 or 3 of the LEDs are not working at all. I've been searching for more info on this but have not found anything. Does anyone know the likely cause of this? Here is a pic of the radio.

 

[1998Exp]

Couldn't tell from your pic which buttons are not illuminated. A a feature of this radio is that buttons that are not functional for the mode selected are not illuminated. May or may not apply to your situation.

Our recently acquired 1998 Mountaineer had the ever so common blank display issue. I resolved thet issue with a Dorman replacement power board. There is however an intermittent problem with the illumination or backlight of the buttons. Also it appears that 2 or 3 of the LEDs are not working at all. I've been searching for more info on this but have not found anything. Does anyone know the likely cause of this?

 

[Mountaineer302]

Couldn't tell from your pic which buttons are not illuminated. A a feature of this radio is that buttons that are not functional for the mode selected are not illuminated. May or may not apply to your situation.

Oh, that pic is just to show the model radio and isn't on. That makes sense. I'll have to run it through all the functions to verify.

 

[Mountaineer302]

Well, it appears that none of the radio's button illumination is working now. Does anyone know where to start looking?

 

[bobflood]

Make sure that you have not turned the dash illumination down all the way with the dimmer switch. Then, check at the radio plug to make sure that you have power into the radio illumination circuit - should be a red/black wire in the radio plug. BTW, I don't believe that the illumination bulbs are LED. Good luck.

 

[CDW6212R]

Most of the bulbs are replaceable, but the display should be all or nothing, meaning that board should solve the issue. As said above many buttons don't illuminate all the time because they don't apply in the current mode etc. I've forgotten that many times.

 

[Mountaineer302]

Yeah, I know that the buttons only illuminate with the rest of the dash lights when the headlights are on. The dimmer switch is not the issue. Although I have had that happen before on a few cars. The rest of the dash illumination works except for the fog light switch, but its power light works. I'll have to figure out how to fix that too.

 

[bobflood]

If the rest of the dash lights work, you have some burned out bulbs. The fog light switch has a separate bulb; you have to remove the switch from it's mounting bracket to see it. You can buy these bulbs from autoillumination.com. Good luck.

 

[Mountaineer302]

Thanks. I'll have to look into the bulb for the switch. As for the radio buttons, It seems that sometimes they work and sometimes they don't.

 

[Mountaineer302]

I have figured out that none of the bulbs are burned out. They actually do not all light up all the time. Some only work during CD or tape use. So, I do not have any that are burned out. The issue I am having is that sometimes they work perfectly, sometimes they barely glow, and other times they do not come on at all.

Does someone know which wires to look at for bad connections? Also, does someone have a schematic showing which connectors on the back of the radio face are used for the illumination?

 

[nimblemotors]

So no answer to the illumination issue? Have same problem with my 98 EB. I just fixed the clock/station display by removing the power supply, but the buttons don't light up. They were flaky before. I want to fix it before I put it all back together. Are their bulbs in the faceplate or leds? I don't want to take it apart and have the buttons go flying and pain to put back together.

ok, so I took it apart, and yes there are leds inside, so they are not going to burn up.
I think the power supply that powers the clock display probably also supplies the 3-5v for the button display, so maybe part of the ps is still not working. I dunno, but I am NOT going to put in an aftermarket radio. I was totally psyched this EX has the stock mach radio. It works great, except the illumination.

 

[CDW6212R]

I wish we knew what is different with the Dorman power supply board, versus the Mach board. I have one but haven't had time to work with it. I would hope it's close enough to be able to make it work somehow.

 

[koda2000]

I wish we knew what is different with the Dorman power supply board, versus the Mach board. I have one but haven't had time to work with it. I would hope it's close enough to be able to make it work somehow.

IDK what's different between the Mach and non-Mach power boards, but I think it's significantly different. I once spoke to a Dorman tech about it and was told it would not work in the Mach radio and that they had no plans to make a power board for the Mach radio. The PO of my '01 EB had the OE power board repaired and modified. Since then it's been working fine for the past eight years.

 

[nimblemotors]

So I asked a guy selling repaired power supplies on ebay, and he said the power supply is only for the clock display, not the buttons.

 

[J_C]

The most likely problem for the buttons and lights is that either the circuit board they're on is cracked, breaking one or more traces, or solder joint(s) are cracked.

Either can be DIY repaired once you find the fault. If you see nothing wrong then it's time to whip out a soldering iron and start reflowing solder joints and using a multimeter to do point to point continuity checks. Since it's intermittent you might want to *gently* flex the circuit board while doing the checks. If you flex it too far, you can cause new damage.

If the board is cracked, add a new wire point to point to keep the connection good and clean the area on both sides of the crack then lay down a wide bead of epoxy to fortify it, making sure it still fits mounted in the radio.

IMO, this is caused by sub-optimal design but made worse by having trucks that bounce around so when you go to press the buttons, it flexes the circuit board more than it otherwise would.

 

[nimblemotors]

I have looked over the faceplate board with a magnifiying glass and see nothing wrong with it.
I am trying to trace the led paths, looking to see where the power comes in. Doesn't look easy,
there are two 88307a chips that connect to the leds. I can't find anything about them, both the anode and cathodes
seem to connect, but honestly this is so tedious..i'd be happy just to get the station buttons to light up,
that is really all i need to see at night. But I think there is probably a single voltage input for all of them that isn't working, which is what I'm trying to find..haven't given up yet.

OK, so some leds are in series. But the power appears to come from the same power supply board as the clock display. It also connects to the other board, so possibly it comes from that board and also go IN to the power supply, but there are clear inputs to the power supply from the main board. All I can do today. I suppose I can disassemble the whole damn unit to get to the main board inside. sigh

 

[J_C]

Yes it is tedious. I'm in the process of trying to convince myself to let my '98 slowly decay.


Regardless, if you have power in, at some point you have a break in-between that and power out/ ground.

 

[nimblemotors]

Here is the update. Turns out the power supply DC-DC converter does not power the button leds. My track tracing was in error.
The DC-DC has a 12v input, and puts out -32v, -38v, +5v, +3v. The +5v does go into the board to power one of the led control chips.
The power for the leds comes from the main board. My tests show it isn't working, no +5v on the input pin from the main board.
However, there were three other switched +5v outputs that switch on when the lights are on, they go to the control chips to turn on
the leds. So instead of taking the radio all apart to get to the main board, I just made all the leds on when the lights are on,
instead of having the processor customize them by mode. The control chips just connect the negative to ground, so I just soldered
those leads right to ground. The second chip I removed and soldered the leds traces to ground. There are different groups of leds,
so that was a pain to determine which chip pin do which leds. Then I jumped over one of the +5 inputs to the led power,
and now it works! So turn on the lights and all the buttons (well most all, the channel buttons do) light up.
So a lot of work, but I am happy camper now.

 

[CDW6212R]

Great work.

I like how the specific lights come on for the needed functions/features, and others turn off. But having them all on is much better than them all being dark.

 

[donalds]

My mach unit did the same thing
What it was was the power supply board
It has a tin radio frequency insulation cover
Look under it remove it find the bad mine was melted solder joint suck up the old solder and resolder

Mine had the solder melt onto the tin shield making a short
Fixed her rite up