Pioneer VSX-808RDS IR problems (Was: Testing an I.R. Receiver)

[Terry]

A few years ago, Elektor published a circuit design from a reader using a supercap. Until a very few years ago, dynamo cycle lighting was still very popular on the continent - in the Netherlands, Belgium and France (most of the dynamos I saw for sale were made in France) at least.

With dynamo prices at around €5 it was a no brainer really - after all, how many dry cells can you buy for €5?

The only problem with dynamo lighting, of course, is that when you stop, the lights go out! This design used the dynamo to charge a supercap and then a level detector connected a couple of high intensity red LEDs  across the supercap when the dynamo voltage dropped below a preset level.

Simple, but effective!

[Old Sparky]

Further checks (mainly to figure out how the different functions on the Remote Control were accessed, I was able to establish that all did work, so the owner has had the Pioneer back in full working order. As I've heard no more from him since the day he collected it, I'm at least 99% certain that it continues to function as designed. Whether I want to tackle another of these, or anything similar, is a moot point!!

[Old Sparky]

Not the end of the Saga! Yesterday it's owner brought the VSX808 and it's remote back, saying that the Remote wasn't working again. Checking the control with my I.R. tester proves that it is at least transmitting signals, but the Rx isn't responding to any of them, although ait otherwise functions as it should. Haven't yet had time to check the 808 itself, but I'm wondering what has failed this time!

[Murphyv310]

Don't you just hate bouncers. Always on the ones you've spent hours on and the most awkward ones to dismantle....... It would drive you to drink.

[Old Sparky]

Don't get too many, Trevor, but I 100% agree. Re-reading posts on this thread, I wonder if the ceramic resonators in the Remote are faulty. Before dismantling the 808 (not a 5-minute job!), I 'll check those first.

[Refugee]

That is why I will not repair lap tops.
Once the owners get hooked into you they will not go away.

[Old Sparky]

Since my last post, having dismantled & checked the Remote Control, I've ordered some 3-terminal 4.00Mhz filters, so, when they arrive from Hong Kong, I'll replace the one fitted, which should restore operation. There are few, if any, other components in the R.C., which would be easily changeable in any case.

[Old Sparky]

I've now fitted a new 4Mhz Filter and checked/re-soldered the battery terminals. Remote still not working! Next step, I guess, is to rig up a 3v DC supply, so I can power the remote with the covers off, so I can connect either a 'scope or Freq. counter to see if there is 4Mhz present. My variable bench PSU only goes down to ca. 5.5v. I built it many years ago to a design in PW, and could modify it so it goes down to zero volts (as does my other, 10Amp PSU), but it's a time and inclination thing. Too much else to do!

[Murphyv310]

Is the remote producing its signal from the LED? Check it with a digital camera or smartphone looking at the led, or even close to a medium or long wave radio for pulsing when holding a button down.
Its very rare for them to go off frequency.

[Mark Hennessy]

This is a very frustrating thread to follow...

I don't understand why the remote was pulled apart - never an easy or harmless operation - when it was apparent (from post #33) that it was producing IR signals. If there was any doubt about the timing of these signals, then simply connect a 'scope to the output of an IR receiver! Yes, remotes can fail, but overwhelmingly it's because of bad battery contacts, worn buttons, dry joints (usually on the LED when it's exposed at the end of the remote), physical damage, etc. I've never had to change the resonator in a remote. Perhaps I've been lucky.

Earlier, we established that the fault was apparently the super-cap, and that the remote was absolutely fine (leaving aside the "user error" that meant that some of the buttons didn't appear to be working, when really they were producing codes intended of other equipment). So, given that the receiver had been comprehensively taken apart and probed, why was it most logical to assume that the remote control had suddenly stopped working? First rule of a bounce is, surely, "what did I disturb?".

How long had your replacement supercap been sat around? In your shoes, I'd go straight back to that - they have a finite life, whether used or not. Then, I'd get the 'scope out and follow through the signal from IR receiver until it reaches the microcontroller. Looking back over the thread, I see that I urged you to do that, but see no evidence that you did. Are you struggling because your working Philips 'scope is still in your house?