PHILIPS/ROVER R860 Sibilance

[jonnybear]

I am hoping someone can come up with an answer on this one, on this radio it is becoming more and more impossible to listen to speech due to sibilance, it is on all stations on the FM band, I know it is old having had its 21st birthday, but would prefer not to swap it with a new one as I would like to keep car original.
John

[G6Tanuki]

In times-past I'd suggest that the discriminator-coil probably needs an alighment-tweak; but having recently disembowelled a similar-age Sony head-unit which had become unusably-deaf on FM, I couldn't actually recognise a FM discriminator-coil in there (there were only about four chips used for the entire AM/FM receiver, audio processing, remote-controls/display-control and station-memories, all SMD types with vast numbers of legs).

[ukcol]

Change the electrolytic capacitor in the ratio detector John. Give the detector coil a tweak as required. From my hospital bed. WHAT a HERO.

[simpsons]

Searching the web shows that the R860 radio used by Rover was used also by a number of Car Manufacturers. Unless I'm mistaken, it is a Philips 22DC745 and there is no simple ratio discriminator for FM.

The service manual can be downloaded.

Good luck

Chris

['LIVEWIRE?']

Not sure about the Philips model no., Chris, but in the 80s & 90s, Philips stereos, badged & numbered appropriately, were fitted by BL/Austin Rover, Vauxhall, and others. AFAIK you're right about there not being a FM ratio detector in them. I still have some service manuals somewhere, but without looking at one I don't recall what the FM demod. circuit is - possibly it's akin to that in radios using the CA3819 I.C. What i do recall is that the I.A.C. (Philips term for the FM Noise reduction circuit) is connected between the I.F./demod. circuit and the stereo decoder.

[jonnybear]

Many thanks to all for information, a circuit diagram would help a lot, do not seem to get a download just go around and around in circles.
John

[Maarten]

Please have a look at the proper model number, it should be on the radio. If not on the large label on the top, maybe on a smaller label.

['LIVEWIRE?']

Philips Car Stereo Model numbers of that era were always in the form '22DC7xx' or '22DC8xx' (at least all those I remember servicing were!') As Maarten says, the Philips model No. should be on a large label either on the top or bottom cover. A picture of the stereo should help us to identify it. Do remember that the radio will have a 3 or 4 digit security code, so on no account disconnect the stereo or remove it from the car unless you know the code number. (Hope I'm not too late with this advice!)

[jonnybear]

Some how I seem to have misplaced extraction tool, so as soon as I can find it I will get radio info. here is a picture of the radio.
John

['LIVEWIRE?']

I can't provide a definite model n. from that photo, JB, but it is one of the 22DC7xx or 8xx series, and I may have a service manual or circuit diagram somewhere. The extraction tools are two 'U' shaped hooks, which push into the holes either side of the fascia, but, repeating my earlier comment, please do not remove & disconnect the stereo unless you have the correct Security Code for it. Once disconnected from the +12v supply, the stereo will be 'locked', and won't work again unless and until the code number is entered.

[simpsons]

Well, well,

Just goes to show, follow the paper trail and all will be revealed.

I got the 22DC745 number from a Rover website.

Now just to prove me wrong, blow me down, these radios are for sale on eBayand show quite clearly model 22DC594/60L. The schematic is easily downloaded from electrotanya.

Sorry about that, can't think why I didn't use my common sense!

Chris

[jonnybear]

Thanks to all again, I have found extraction tools, This is the label rather grotty attached to the radio, as far as I can make out it is a Philips 22DC594/60S.
John

[jonnybear]

Originally Posted by simpsons

Well, well,

Just goes to show, follow the paper trail and all will be revealed.

I got the 22DC745 number from a Rover website.

Now just to prove me wrong, blow me down, these radios are for sale on eBayand show quite clearly model 22DC594/60L. The schematic is easily downloaded from electrotanya.

Sorry about that, can't think why I didn't use my common sense!

Chris

I have just down loaded 22DC594 from elektrotanya and it looks a completely different animal, would not except /60s.
John

['LIVEWIRE?']

The '594, IIRC, was completely different apart from the P6 Cassette Mechanism. However, as noted, I have several Philips manuals for the 22DC series. I'll look them out as soon as I can.One may be identical to the R860. In the meantime other on-line sites such as 'HiFi Engine' may have them available

[Goldie99]

There were various 22DC594/XXX variants, some with CD changer capability, some without, depending upon what the car OEM had ordered.

22DC594/60E ROVER R760
22DC594/60B R770 BLACK ROVER
22DC594/60S ROVER R860
22DC594/61L R770 GRAY DISCOVERY
22DC594/65 PEUGEOT
22DC594/65B PEUGEOT
22DC594/65E PEUGEOT
22DC594/62B RENAULT
22DC594/62E REN SAT 6010
22DC594/62F RENAULT
22DC594/62L REN SAT 6010
22DC594/62S RENAULT
22DC594/62X RENAULT
22DC594/35 CITROEN
22DC594/35X CITROEN
22DC594/72S RENAULT

[simpsons]

The attached picture illustrates the ic types often used in Philips Car Radios together with their function.

Should the ic types match your radio then, a little lateral thinking maybe required. One thing for sure, with microprocessors, it isn't a question of twiddling a coil.

On the plus side, the vintage of your radio will mean you don't have the difficulty of removing lead free soldered SMC's. On a TomTom repair I had to resort to plumbers flux to free the board of such solder and that was before I got the blighter out which needed changing. Thank goodness it didn't have 32 legs!

Good luck

Chris

[Maarten]

Originally Posted by 'LIVEWIRE?'

I can't provide a definite model n. from that photo, JB, but it is one of the 22DC7xx or 8xx series, and I may have a service manual or circuit diagram somewhere. The extraction tools are two 'U' shaped hooks, which push into the holes either side of the fascia, but, repeating my earlier comment, please do not remove & disconnect the stereo unless you have the correct Security Code for it. Once disconnected from the +12v supply, the stereo will be 'locked', and won't work again unless and until the code number is entered.

It will only be locked if the security code is indeed activated. It can be switched off.

['LIVEWIRE?']

I was aware of that, Maarten, having worked as a repair engineer for 23 years, but thought it worthwhile pointing the security code feature out to the OP, in case he wasn't familiar with it.

[jonnybear]

Thank you all for the feedback. Yes I to have been in the trade for many years
well over 50 of them, as livewire says codes are always worth a mention. would be great to get hold of a circuit diagram though.
John

[pichacker]

By now the EEProm may well have worn out as well. I replaced many that would not remember the last settings before power off or would not store new updated channel settings.