Fixing radio - where do I solder?

NoTicketsPlease · 07-24-2006, 08:15 PM

Hi, im trying to fix my radio display in a ford 98 explorer. Everything works except the lcd display. According to others on the web I need to solder the cold solder joints on this board. Are they the 5 duller looking posts surrounding the black box(2 on left, 3 on right)?

Any tips on soldering these?

Also, does the board look like it would even work given the burns it has?

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Shadow · 07-24-2006, 09:58 PM

Cold solder joints are cloudy. Good solder joints are shiny. The joints near the big white arrows are good. The joints around the SMT resistors R1053 1056 1052 all look craptastic. The IC (Integrated Circuit, little black box thing, looks like it's got some cold solder joints too. Can you send me those instructions? My mom's 00 Explorer display is crapping out.

NoTicketsPlease · 07-24-2006, 10:09 PM

This is a collection of notes I put together from the web:

98 FORD EXPLORER Radio display fix
Apparently bad solder joints on power supply circuit board.
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just resolder the joints on the powerboard in the upper left corner of the radio
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Fixed mine today. (1998 Exploder with CD/Cassette) ?TIPS:?Use a coat hanger to make the withdrawal tool. Make both tools as long as you can, using the full length of each side of the coat hangar wire (6-8"?). This allows you to wedge the wires apart with your forearms while pulling out the radio.

Remember you only need to remove the 2 small black screws on each side of the black faceplate on the front of the radio, and the one 3/4" screw on the top right side when viewing the back of the radio.?(I completely disassembled the whole radio, missed this article until afterwards:-)
Resolder ALL solder joints with a fine tipper solder iron it doesn't take that long.

***When resoldering the 1 Watt and 2 Watt resistors pull them away from the board as much as you can and still manage to solder the underside of the board. This will get them off the surface of the board and increase the air flow around them, and increase their cooling capability. Imagine a 9 Watt light bulb in the tiny confined space where this stuff is located. (THIS IS A VERY POOR DESIGN!, as is the large black "heatslug" on the back of the unit. This should have a larger surface area, like the thin long black fins you see inside the top of your home stereo. CD's popping out of this radio are sometimes well over 100 degrees.

If you have an extra few minutes, consider drilling some holes in the tin RF shield that covers the top of the board for extra cooling before reattaching.? Place the board with the RF shield back in the chassis and use a black magic maker to trace the cooling slots on the side of the main chassis onto the tin RF shield on the power supply board. Then pull the board out, remove the shield (desolder), insert a piece of wood (the end of a 1" x 2" probably would work, I used a piece of scrap) Then drill 10-20 holes in the shield over the outlines you traced on the side of the shield. This should allow some of the heat to escape out the side vs. building up in the chassis.
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You must re-solder the connections on the bottom of the power supply board. Unless you have access to an electron microscope you will not be able to see the cold solder joints. Some cold solder joints appear to have a dull finish and not shiny. But these components are so small, the best bet is to re-solder them and apply some new solder to the joint.

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Here's the directions that helped me...Good Luck:?By opening up the radio you will find a narrow display power board. With in the left side of the radio (faceplate toward you). This board has a metal cover soldered to it, with a toroid (wire wound doughnut) inside on one side, and a bank of surface mount resistors and capacitors on the bottom side. One end of the board (SCR heat sink) is screwed to the heat sink at the back of the radio, the board is secured with 2 metal bend-tabs, and it has a white mini connector on the other end which connects to the faceplate. Remove the board from the radio.

On the bottom of the board look for surface mount components R1057/C1071/R1058/C1083/R1064. The colder these resistor/capacitor chipsets get, the brighter the display. I left the car out in the +5 f degree weather and the display worked until it warmed up a little. That is how I was able to track it down to these temperature sensitive parts. Freeze-it also helped after I narrowed it down to a few components.

NoTicketsPlease · 07-24-2006, 10:15 PM

Quote: Originally Posted by Shadow

Cold solder joints are cloudy. Good solder joints are shiny. The joints near the big white arrows are good. The joints around the SMT resistors R1053 1056 1052 all look craptastic. The IC (Integrated Circuit, little black box thing, looks like it's got some cold solder joints too. Can you send me those instructions? My mom's 00 Explorer display is crapping out.

Im not very good at soldering. I guess I would need a very small soldering tool?

Also could I solder over the liitle numbers on the resistor? (the small black squares on each one?) Or would that screw it up?

Shadow · 07-24-2006, 11:37 PM

That would short the caps out. The ends have to stay seperated. According to the last part of your directions, you just need to mess with the resistors in the bottom left of your picture but the middle says resolder everything. Just get a 15W iron and be CAREFUL.

NoTicketsPlease · 07-25-2006, 01:09 AM

I tried soldering the upper ones but no luck. At least the thing still works. Im going to try the bottom left ones next but they look okay.

Shadow · 07-25-2006, 12:54 PM

I fixed my mom's radio just now. Those things you were referring to in your first post go to high wattage resistors on the top of the board. Yes, solder those. I soldered both sides of all the resistors and caps around that IC as well as the ones on the bototm of the board. The thing works perfectly now