LUMINESCENT DASH LIGHTS / EL Dash Panel Inverter Replacement

[Frank W.]

Topic: Replace EL Dash Inverter.


Bus Type: 1985 BlueBird Wanderlodge FC Date: January 21, 2009

My Electroluminescent (EL) lower dash display stopped working; only history is that about 3 years ago same problem developed and I replaced the existing OEM Endicott units with the same type. These units worked fine then subsequently just “faded away”, after a estimated total time of perhaps 20 hours use.

I bought a new inverter from Cape Innovation (also trading as Dupree Products), this is a different unit and seems much more robust.

Inverter Location & Dash Access:

For clarity, I’ll use the term lower dash to mean the lower switch panel just underneath the steering wheel that has most of the function switches, gas and volt meters. Upper dash refers to the panel forward of the steering wheel with the tachometer and speedometer and other gauges. My repair did not involve the overhead dash with the altimeter, spotlight and AC controls. This overhead dash EL panel is supplied by another inverter located behind this panel (based on the soft buzzing I hear from the OEM inverter).

The OEM inverters look like two “blue ice cubes” with yellow warning labels. They are mounted behind the upper dash in the center of the console. To gain access to the entire area you remove the outer edge trim from around the lower dash, once removed this panel can be lifted up and forward about an inch. In the center bottom edge of the upper dash there is a metal brace with a screw that holds the upper center portion of the upper dash secure, remove this screw. Look next for a large headed screw in the lower left corner of the upper dash, remove it. The right side is secured by the rearmost screw on the CB mike holder; once this is removed the upper dash is free to move forward about 2 inches. The mass of wiring makes further movement difficult. If needed, you can disconnect the harnesses and remove the panels, but I did not have to do this. Look in from the top and you should see the “blue ice cubes”

Checking Inverters and Wiring:

The inverter(s) are supplied with 12 volts when the headlight switch is “on” and the dash dimmer rheostat is turned up. Look for your power supply coming off the rheostat and test for 12 volts DC and good grounds going to the inverter(s), these were black (+) and white (-) on my coach. Look carefully under the dash panels…the 120 volts supplied via the inverters is delivered via wires (green & black) that terminate at “silicone blobs” on the dash panel…be careful here, do not pull the wires off the panel. Check for 120 volts AC coming out the inverter feed terminals with the wires attached. Do not run inverter with no load. Some installations use two inverters in a 120 volt parallel output set-up. Why I have no clue as this makes no sense to me.

Next, I suggest that if you have good wire attachments, 12 volts going into inverter(s) and nothing coming out, you’re in the same boat I was. Get a new inverter and replace the old one(s).

Clean your rheostat and headlight switch with spray type electrical contact cleaner, (NOT WD-40!). I replaced my two OEM type blue ice cubes with one new inverter. The inverter I received from had no markings, wiring code is RED=12 volt + DC; BLACK =12 volt DC ground; WHITE is 120 volt AC out. Attach wires and secure the inverter behind dash. Mine fit well on the left side behind the upper dash secured to the wood.

Carefully check all your dash lights and wiring before you reassemble dash…it is easy to pull off a gauge wire and not notice until you have it all back together.

Photo 1: shows OEM blue cubes. 2: shows new inverter output. 3: new vs old Inverter

[dlefty]

Nice write up! I think my rheostat needs to be cleaned. My dash is very flaky!

[Bill Pape]

Frank,

Thanks for taking the time to write this up.
Good job

[tulipvendor50]

Frank, I have purchased new EI inverters from Steve already, do I understand you correctly that you have one for the whole bottom dash now instead of two.
I bought four of them, one for overhead, one for upper dash, one for right lower dash and the last for left lower dash.
It appears that the lights are bright enough, would not the total dash be overloading the inverter?

Thanks Frank I can check mine now.

[Frank W.]

Originally Posted by tulipvendor50

Frank, I have purchased new EI inverters from Steve already, do I understand you correctly that you have one for the whole bottom dash now instead of two.
I bought four of them, one for overhead, one for upper dash, one for right lower dash and the last for left lower dash.
It appears that the lights are bright enough, would not the total dash be overloading the inverter?

That is a good question and the expert is not in the room at the moment...as he lives "up there" in Canada with you. I hope Steve B replys on this.

I bought two for the lower dash...but on getting them and looking over the OEM installation, size of the wires (indicating what the system AMP demand range is), size of the new inverter and the wires...I made an educated guess that one inverter would power the entire lower and upper dash EL modules. The way mine was apparantly OEM wired, the two OEM inverters were paired and fed all the modules...but the result of this system was short term failure of the inverters. I do not want to pair them or change the wiring harness to separate the EL panels electrically.

Of course the overhead EL panel has a separate inverter.

My decision is just my SWAG...time will tell.

[innovative1]

Mr. Moderator please forgive me in advance if I should have started a new thread. On the 90SP there 4 of these "Ice Cube" inverters located behind the access panel on the front cap. Currently no EL panels illuminate. I have verified 12V DC in and no AC out using true RMS meter. As memory serves me all 4 are wired in series but I'll need to reverify. I have in my possession some of the Dupree replacement units. At first glance I may have a real estate shortage if I need to install 4 new units. Definitely there appears to be some variation from model to model how BB approached this. Any one else done (hopefully successfully) this retrofit before? Have I found all the dash inverters or is there another one over head? Insight would be greatly appreciated.

[iamflagman]

Originally Posted by innovative1

Mr. Moderator please forgive me in advance if I should have started a new thread.

You did it the right way, by adding the title "El Dash Inverter replacement on a 90SP" to your post, that way when someone replies to your specific issue, that IS related to the main topic, they should post their reply to you by adding Re: El Dash Inverter replacement on a 90SP in the title box at th top of their reply.

Thanks for doing it that way.

[innovative1]

Alright, I started with out you. Cleaned the contacts on the switch and dimmer.There are 4 inverters with all wired in parallel. Each 110 in addition to the parallel wiring appears to have an individual load. My guess is this provides some sort of load balancing or fault tolerance. I disconnected the #1 inverter and connect a replacement unit from Dupree Products. Energized the circuit and hooray I have some EL at the dash. The following dashes lit up:
Left hand controls- Retarder, Cockpit lights etc.
Both upper instrument/switch dashes
Lower dash except for lower right quadrant- it appear to be trying though only when turned up at full bright.
Right hand lower dash (stereo) same as lower right quadrant of main lower dash.
Nothing on the overhead. The Blue Bird Parts Catalog describes 2 Inverters, Ceramic EL, RH Upper Dash, Upper dash for a 90WL so this may turn out to be an additional scavenger hunt.
It did seem like I really had to turn the stat up to get things lit up.
Any one see any reason not to replace an additional inverter on the other end of the chain (#4) and repeat the test ?
I have read speculation that the Dupree inverter has more a** than the ERG's. Any one happen to have the specs? Adding one more at a time till they light up seems like a good idea. I'm sure there is a flaw in my thinking and the idea of getting a different kind of "lit up" causes me a little anxiety.
Warbucks, tell me what I'm doing wrong and help me correct the err of my ways.
Woody, tell me what I'm doing right.

[jwasnewski]

I don't have a clue if you are doing anything wrong. My WB has a rheostat above for the top 2 panels and 4 inverters smack dab under the TV where you can place one hand on them. The only reasonable access on mine is to remove the right hand cabinet and come around the side and behind the TV.