Philips 14PV200 TV/Video Combi

[Philips210]

Hi.

I bought my Philips 14PV200/07 TV/Video Combi in early 2001 and I guess it's not had a huge amount of use. Lately it's been a little reluctant to start up. When applying the mains a slight ticking sound is coming from the power supply and the standby/power LED is out. Removing the mains and the ticking continues for several seconds. Powering up again it tries to start up and eventually after several seconds the Standby/power LED lights. Pressing the Program up/down buttons then brings the set on normally.

There's clearly a start up problem with the power supply and from past experience in other sets is often due to an electrolyic cap or resistor fault.
I've had a quick look at the TV main board and noticed most of the electrolytic caps are made by Rubycon and are probably above suspicion. I did a quick in circuit check of the resistors around the control IC and all seems to be well. I'm suspecting the problem may be with the control IC itself (IC7310 type MC44608).

Also powering down after normal operation and then powering up, the set will come on normally. The problems occur again if the set has been left disconnected from the mains for a few hours. On that basis it really points to capacitor trouble.

I downloaded some service information from Elektrotanya. The chassis appears to be designated Delta 2000 with the VCR deck being the Turbo Drive type.
In the service information there's no mention of adjustments and what I was wondering is does the set have a service mode? I think this would normally be envoked by a sequence of numbers on the remote control. Some Philips sets rely on a jumper connection in the control section as another possibility.

Something that's just occured to me. Maybe the ticking sound is actually due to a temporary overload causing the power supply to trip. Perhaps that could be due to an electrolytic that's leaky, possibly in the power supply or in the line output stage etc.

Has anyone had any experience with these sets? Any help would be appreciated. Thanks.

Regards,
Symon

[Sideband]

Not sure I worked on one of these....it was towards the end of my employment with Philips. As you have the circuit can you post up the power supply part? It doesn't appear to be available from this site so no problem posting part of the circuit. Generally as you say, it's either an electrolytic or it could be a high-value resistor associated with the start-up circuit. If there are any lowish value electrolytics (2.2uF - 10uF) in the primary side of the psu, these are a good candidate for checking. Agree that Rubycons are usually reliable but they are not infallible...and the set is now 22 years old or thereabouts.

[Sideband]

Had a very quick look at the circuit. Try checking R 3318 (180K), R 3335 (1K part of the start-up circuit) and C 2323 (22uF supply decoupling to the chip).

[Philips210]

Thank you Sideband, I'll have a look this afternoon and report back.

Any ideas on entering the service mode? I wanted to make a small adjustment to the width and check the EW setting.

Regards,
Symon

[Philips210]

Just been having a look at the set.
I took the chassis out so that I could carry out a few cold checks.
R3318 (180k), R3335 (1k) and C2323 (22uF) all checked out OK. R3318 is a surface mount resistor fitted close to IC7310. The capacitance and ESR of C2323 were fine.
I recalled having a start up problem with a Philips CP110 and that turned out to be the mains bridge rectifier's HT reservoir capacitor. In the Delta 2000 chassis that cap is C2311 (68uF). I removed this for testing and it was again fine so back it went.
Also removed and checked C2353 (100uF 160V) the HT smoothing cap and again the ESR was fine but unusually the capacitance was a little on the low side at 83uF. I compared the values with similar low impedance electros and the ESR was low enough but I'm slightly suspicious of the lowish capacitance value. As the ESR was good I put the original back.

I gave the chassis a thorough inspection and noticed around the chopper control IC (IC7310) the board showed very slight discolouration as if the IC runs on the warm side. Looking at the IC's soldering revealed a few slightly crusty joints. Also, some signs of corrosion on the pins. Using the desoldering braid, I removed the old solder and gave the IC pins a bit of a clean and then resoldered the joints. I couldn't find anything else obviously wrong so decided to put the chassis back in and retest. It started up straight away but that doesn't really prove the fault is cleared. I'll give it another test tomorrow.

Regards,
Symon.

[andrewn]

The fault you've reported is much the same as the fault I had on my Zanussi TV I repaired a few weeks ago. The PSU is IC based and I had to replace all the electrolytic caps in the PSU to fix it despite them measuring low ESR and correct capacitance. I guess there must be some other aspect that had deteriorated that I couldn't measure. The new 100uF mains reservoir cap I think measured 86uF and I was concerned it seemed low but all is fine, in fact all the replacements measured lower so perhaps that is significant.

[Philips210]

That's a strange situation Andrew. You'd think with a low ESR and capacitance reasonably close to normal then the caps would be fit for service. That's how I've always approached servicing power supplies.

I'm wondering if the following scenario might explain it. Supposing the suspect cap reads fine regarding ESR and capacitance but is suffering from excessive leakage current. Would the leakage current mask the ESR reading ie make it look lower, and hence better, than it actually is? In a linear power supply it probably wouldn't be too much of a problem but in switch mode power supplies a big issue. Maybe we should also check the electros for excess leakage current as well. We'd do that anyway if reforming caps but may take it for granted it will be fine in more modern equipment. One other point, the set had sat dormant for many years so maybe some of the caps needed to be reformed.

Tested the set again a short while ago and appears to be working fine at the moment. Time will tell!
One other potential thing I forgot to mention before, on the opto coupler/isolator, I noticed a deposit across the transistor part and some slight corrosion. There may have been tracking across the collector/emitter connections.


Regards,
Symon

[Welsh Anorak]

I find it instructive when testing ESR to heat and freeze the capacitor. Sometimes the ESR will leap up when cold. Of course when you've desoldered the component it's a lot warmer than when in situ so can lead to pardoning a guilty component.

[Philips210]

Thanks Glyn, another good point. I'll try a little heat/cooling next time I check any SMPS caps. I've noticed the fault seemed to be worse when the ambient temperature was cooler so may well be an ESR issue with one of the caps.

Have you any ideas about the service mode for the Delta 2000 chassis? I've tried 062596 MENU but had no luck entering the service menu.

Regards,
Symon

[gallowfields]

with customers sets always found it quicker and more cost effective to change the capacitors first appreciate it if is your own you would like to ascertain the faulty one ,s and of course fit good quality 105degree ones

[Maarten]

062596i is less likely to work as that's for TV's. A TVCR is a VCR for practical intents and purposes since it was mostly designed by the VCR people. I assume they were really happy in Vienna to finally get to design a TV chassis again after all those years ;-) Maybe try some combination of the stop and play buttons, one on the handset, one on the set itself. This should be in the service manual.

[Philips210]

Hi Maarten.

I also downloaded the service information for the slightly earlier TV/VCR Combi which has the TVCR Delta 99 chassis. The information is much more comprehensive and does indeed have the service menu instructions. The Delta 2000 is possibly a supplement to the earlier manual.
Anyway, you were quite correct in what you said about entering the service mode and thanks for your reply.

To enter the service mode:

1 Press STOP on Remote control handset,

2 Press PLAY on TV/VCR

3 Press and keep both of these buttons down for 5 seconds.

The service mode is then envoked. It's fairly instructive thereafter.
To leave the service mode, press Standby.
Hope this will help others that have one of these, or similar sets.

The set came on normally this morning, so perhaps I've cleared the fault (fingers crossed)

Regards,
Symon

[Sideband]

Whatever you do in service mode be careful what you adjust! Some sets have 'option codes' that shouldn't be altered since they define specific functions. The service manual should give a list of them if the set uses such codes. Just giving the warning to others who may not have full service details and just want to 'have a play'!! It could spell disaster if you change something you shouldn't!! That is why the service mode could only be entered by specific non-standard push button operations....it's unlikely to be accessed in normal operation.

I seem to recall that some sets had option codes printed on the type label.

[Philips210]

That's good advice. I certainly wouldn't make any adjustments without consulting the service manual and in any event make a note of all settings before making a change.
A quick look through the options this morning and I couldn't see one for width or EW adjustments but line shift was an option. I'll have a good look through the Delta 99 chassis service manual.

Regards,
Symon