Pioneer CD Changer - Display Flicker / Not loading discs - Page 1
Forum section: electronics / repair

author: aod
author_rank: Newbie
timestamp: December 11, 2020, 05:43:52 pm
content: Hi allI'm trying to see if I can repair my parents CD Player and need some advice.It's a Pioneer PD-M602 CD Changer with a 6 disc cartridge.The reported issue is that it's no longer playing CDs - e.g the tray cartridge mechanism doesn't try to load to the disc - but I noticed a potentially bigger issue, in that the LCD display is flickering.I'm an electronics novice - most of what I know has been through watching videos on EEVblog, but from what I've experienced the LCD flickering could suggest a power stability issue, which might also mean the loading mechanism isn't getting enough voltage to operate properly?Could it be a bad capacitor? I have had a look around the power supply board and can't see any tell-tale signs of bulging or bad caps, but it may not have got to that point yet.I don't have a multimeter or the skills for this - is there anything else I can do to diagnose and fix this, or does it need more professional help?

author: bob91343
author_rank: Super Contributor
timestamp: December 11, 2020, 06:53:02 pm
content: The display problem could be as simple as a ribbon cable working loose. You can't tell a bad capacitor by its appearance most of the time without test equipment. You can try by replacing the largest electrolytic capacitors one at a time, but the shotgun approach is labor intensive and has pitfalls of making errors. You at the very least should have a portable meter, either analog or digital, for making some crude measurements. First obtain the service manual and try to understand it.

author: aod
author_rank: Newbie
timestamp: December 12, 2020, 12:05:54 am
content: Quote from: bob91343 on December 11, 2020, 06:53:02 pmThank you - my initial assumption was perhaps it was power related due to the 'pulsing' type of flicker of the display (about 3-4Hz), which could also impact the disc loading mechanism which is the main issue. After you insert the cartridge, if you press 'Disc 1, Disc 2, etc or 'Play' it would normally load the disc into the playing area, but it doesn't do that now. Instead it makes a half attempt, nothing really moves, (there is a short soft mechanical clunk but it then stops) and there are no errors displayed but it doesn't take a disc or play.I'll have look into the ribbon, but I think I'll coax myself into multimeter world and get learning as it's going to be essential in the long run. (I'm a hobbyist just starting out).Can I get away with one of the cheap £10-£15 multimeters on Amazon - I know you should invest in a decent one, but I'm not planning on doing loads of this - just occasional so I need something cheap to start with.

author: bob91343
author_rank: Super Contributor
timestamp: December 12, 2020, 06:30:53 am
content: Good show! However I don't like Amazon. Nearly everything they sell is cheaper elsewhere, often by a lot. Don't knock a cheap DVM; the worst of today's units is better than most of the older ones.Your problem could indeed be power supply capacitors and the meter will let you know. It could also be loose connectors or a bad solder joint or switch.

author: aod
author_rank: Newbie
timestamp: December 12, 2020, 11:48:43 am
content: Excellent thanks!I actually watched Dave's EEVBlog #75 Digital Multimedia Buying Guide for Beginners last night - well about half of it!It's incredibly informative, but seems to come across as 'don't spend less than £100/$100 - which is way more than I really wanted to spend. My main concern is safety and the required features for basic diagnosis - mostly on things like Audio devices, Retro computers and related power supplies.Am I right in thinking you don't need to have such devices plugged into the mains to be able to check the health of components?If so, does that mean there is less chance of danger with buying a cheaper meter that has less of the safety features Dave talks about in the video?I'll probably be happy to spend around £20-£25 for now.

author: bob91343
author_rank: Super Contributor
timestamp: December 12, 2020, 06:50:31 pm
content: Don't be overly concerned with safety. The best safety device is your brain. And I disagree that spending more on a meter will get you anything tangible. In the old days you could save money and get an almost worthless VOM at 1000 Ohms per volt but that's not available today. The cheap meters all have at least 1 Megohm input resistance, plenty high enough for most work. And more accurate than you will ever need.When it's time to get serious with electronics, the meter will still be useful and you will want more sophisticated instruments such as signal generators, oscilloscopes, LCR meters, variac, soldering tools to add capability without obsoleting the little meter.