Pioneer headunit display gone wacko? Any ideas? - Page 1
Forum section: electronics / general

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 19, 2013, 08:33:38 am
content: This unit was working fine till yesterday morning, when the display stopped working.It will now intermittently do the following:Does anyone have any ideas why? I resoldered all the pins on the SMD chip that looked like the LCD driver, but that did nothing.Its weird how the image seems to scroll, or is distorted, not just there, or not there...

author: David_AVD
author_rank: Super Contributor
timestamp: November 19, 2013, 08:37:22 am
content: Does it have a flex cable going from display to driver board?

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 19, 2013, 08:38:34 am
content: Quote from: David_AVD on November 19, 2013, 08:37:22 amIt does, but with the face plate dismantled, and connected to the headunit, poking and pulling the ribbon cable appeared to make no difference.

author: SLJ
author_rank: Frequent Contributor
timestamp: November 20, 2013, 02:22:00 am
content: Always check voltages first. If any seem a bit out of spec check caps. Odd voltages can drive things nuts.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 02:12:02 am
content: Poking around in this today, on the bench, and while I found a 5volt supply, as well as 3.3volts, I also found what seemed to be 9volts, as well as 15.6volts? yes, one of the regulators appears to be boosting the voltage....But I have no clue if these voltages are correctthe 15.6volts does seem to go to the front panel though...

author: Six_Shooter
author_rank: Regular Contributor
timestamp: November 23, 2013, 02:31:12 am
content: The display driver should be in the face itself, and the ribbon cable between the main unit and face being mostly for control,

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 02:35:14 am
content: I've reflowed most things in the faceplate, and it didn't help, so I started checking voltages in the rest of the unit.... as my alternator does give 16+ volt spikes, which could have damaged something in the power supply.

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: November 23, 2013, 02:38:20 am
content: heres a service manual :http://elektrotanya.com/pioneer_deh-5200sd_5250sd_5290sd_crt4508_sm.pdf/download.htmlOn page 25 theres a panel test .

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 03:30:01 am
content: Alright, this is toast.Probably didn't help that I powered it up with two pins shorted on one of the ICsNow not only does it display an intermittent image, but it also displays garbage...

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 06:17:43 am
content: swapped the Pioneer for an Eclipse headunit I already had...Set the subwoofer gains...turn the volume up, "music" turn it down, and the subs keep playing a constant tone at full volume... motor boating? at volume 0, the headunit mutes, and the subs go silent... volume 1, loud constant tone

author: David_AVD
author_rank: Super Contributor
timestamp: November 23, 2013, 12:24:22 pm
content: Did you walk under a ladder whilst carrying a black cat? lol

author: Zbig
author_rank: Frequent Contributor
timestamp: November 23, 2013, 09:38:28 pm
content: Quote from: David_AVD on November 23, 2013, 12:24:22 pmEither this, or his house has been built on some ancient aboriginal people's burial grounds. I couldn't possibly think of any other sensible explanation.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 10:28:39 pm
content: I got made redundant on Wednesday?anyway!I'm wondering if possibly flat batteries might have increased the chances of it happening...The sub stage amplifier actually doesn't have its RCA inputs tied to battery ground, they're isolated, so this isn't a ground loop.I grounded the headunit to the 4ga cable that runs to the front stage amp, as a 50mv difference in ground potential was causing the sub amplifiers to go into protect with the old headunit...

author: Six_Shooter
author_rank: Regular Contributor
timestamp: November 23, 2013, 10:46:21 pm
content: Why would you run long ground cables instead of using the chassis for ground?I've had FAR less problems with both noise and charge in a system when using the chassis than using long runs of ground wires. FWIW, I've worked as car audio install tech for a couple decades, and have tried a few things on my own, along with repairing many systems installed by other people, and it always baffles me when people don't use the chassis for ground.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 10:52:28 pm
content: Quote from: Six_Shooter on November 23, 2013, 10:46:21 pmWhich run?I've had much more success using a single point ground, such as the front battery.When the headunit was grounded to the chassis, I had a 50mv difference between headunit, and rear amplifier ground, which resulted in the amplifiers going into protect. (the sub amp has a reference between battery ground, and headunit ground)I've also used this setup with just the front battery, and 300amp alternator, hence the two runs of 0ga cable (500 amperes) from the front to the rear.The chassis makes a horrible ground, especially in a high current situation... most panels will only be spot welded together, not seam welded, and overtime, moisture gets between the two panels and creates corrosion.

author: Six_Shooter
author_rank: Regular Contributor
timestamp: November 23, 2013, 11:06:34 pm
content: Quote from: AmmoJammo on November 23, 2013, 10:52:28 pmI've built plenty of high power systems myself, many kW at a time...The chassis does NOT make a horrible ground, I see you've been perusing the car audio sites and listening to the "gurus" that only read what other "gurus" say. It's because of this that I don't go on any of those sites anymore, so much bad, bad information on them, that gets repeated so often it's considered to be "gospel".I'm not saying that the chassis as a ground is perfect, the issue is that if the many different sources and loads are not dealt with properly, then you will have issues.I can't count the number of systems I've repaired and improved simply by grounding the components to the chassis and making proper ground connections at the battery, engine and charging system.I can't see how that 50mV difference caused the noise problem, I've measured higher on many systems and not had any noise issues, using other brand headunits.What I HAVE found is that due to the different isolation techniques used by different manufacturers that certain head units did not play well with many amplifiers on the market, Pioneer wasespeciallybad for this. Many times we had to install decoupling capacitors on the RCA shield to the head unit to rectify it, running an additional ground hadneverremoved any noise that occurred. It is because of this that I don't use Pioneer headunits, as much as I do like Pioneer, when designing a multi component system, though the problem seems to be less so in recent years.I'm just going by many years and many thousands of system installation experience, that there are many myths floating around that are taken as gospel. I've tried the many different ideas that pop up from time to time, the only ones that work consistently are the ones based in actual electronics theory, nit some idea that someone had based on something they didn't understand about electrical currents.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 23, 2013, 11:14:23 pm
content: Quote from: Six_Shooter on November 23, 2013, 11:06:34 pmI didn't say noise, I said the amplifier would shut down.However, directly grounding to the front battery did also reduce the noise, as this sub amplifier tends to induce noise back into the headunit, and entire electrical system in the car.Quote from: Six_Shooter on November 23, 2013, 11:06:34 pmPioneer headunits aren't isolated? the RCA ground has a pico fuse on it... if you have excessive noise when using a pioneer headunit, its because you stuffed up the grounds, and blew the fuse! Not pioneers fault.

author: Six_Shooter
author_rank: Regular Contributor
timestamp: November 24, 2013, 12:46:48 am
content: Quote from: AmmoJammo on November 23, 2013, 11:14:23 pmUhhh, no...Many people I know in the industry all say and have the same experience with Pioneer headunits. I found that if I swapped out amplifiers to a different brand, the noise would go away, swap the original amp back in but with a different head unit it was fine. I know there was a certain combination of head unit and amplifier we would avoid a few years years ago, because EVERY system with that combination of Pioneer headunit and that particular couple of brands of amplifier, I don't recall the brand off hand, thinking it was JL and Audison, maybe, would have noise. swap to a different brand headunit and the noise was gone, EVERY time. Nothing blown, nothing damaged, all grounds measured within less than an ohm, or by voltage difference, less than 100mV, usually alotless difference.Pioneer went downhill after about 1995, before then, they were excellent, with only a few brands having a better headunit, Alpine's 7909 being the reference, back then. I actually own a Pioneer DEX-M88 that was considered to have NEARLY as good sound quality as the 7909, but with more features. Unfortunately I had a friend modify it to increase the output on the RCAs (back before I got into electronics) and now it has plenty of noise in the output where it was clean before then. If I can find the original components that he swapped out, I'll put them back in and get it back to original, even though I really have no plans on ever using it again.

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: November 24, 2013, 01:07:09 am
content: lol