Hitachi CNP860 70s ctv

This rang a bell !  http://www.forum.radios-tv.co.uk/viewtopic.php?f=5&t=4515

I remember the CNP190 and 192, we sold other later Hitschi sets but I don’t remember the model numbers or they much about them.

The 190/192 for me were very reliable, odd tuner or tuner push buttons and thats about the faults I had with them. The later quick heat Hitachi CRT’s were poor but again I saw few other faults.

Are you sure about the model number? I don't recall a CNP860 but do remember a CSP680, 17" which used a similar chassis to the 190/192 with an 8 (I think) position rotary preset tuner. 

Incredible reliability other than a fragile aerial socket and  tuner mechanism.

John.

I've looked in all my books obviously ignoring any prior to 1970, I checked through to 1982 nothing mentioned. It must exist as Alastair mentions the exact same model on Vrat 1 thread that Doz linked to.

I have the CSP680

Manuals for the CNP860 are advertised, $7.99, probably other prices on offer but I cannot find any free ones and only a few  web links to the model.

So I've checked Radio & Television Servicing right up to where my books stop which is 1982, nothing.

I've got Trader sheets up until 1980 and also indexes, nothing mentioned in any about the CNP860.

Finally I've got ERT up until 1980 and again many indexes not one mention of the CNP860. The last Hitachi I could find was listed for 1980 and that was the CNP192.

No mention on Radiomuseum either.

Are we sure this TV is 70's? I've no idea if its in that decade. How about a photo of the set.

p.s.

As for those online manual sites, be very wary!

ERT 1980 for the CNP192, I thought the information would have been available earlier, the model was introduced in 1974.

Still that doesn’t  help with the CNP860 problem. 

Just a thought, is this a model imported from Germany or Hong Kong.

I ask because I had a few CNP190/192 type sets brought into the shop for conversion to the UK system, bought overseas and brought home when they moved back to the UK. I cannot remember the model number.

Conversion was straightforward, set the mains voltage and alter the sound. I think Hong Kong was 6 MHz but could wrong.

The vision IF could have been realigned for the wider bandwidth but I found it not needed. Pictures were excellent.

Posted by: Nuvistor

ERT 1980 for the CNP192, I thought the information would have been available earlier, the model was introduced in 1974 

That's correct Frank it was, I was just reporting on what and where, in the ERT index listings it was located.

I've over 5,000 trader/ERT sheets but only covering up to 1980 and all the R&TS books from post war to 1982. I'm wondering if it might be later than 80/2 also if they didn't list the CNP192 until 1980 then maybe the CNP860 was also delayed for inclusion. Does seem odd though. I did check indexes back to 1973, Hitachi is mentioned but still nothing for this elusive set.

As you can imagine I've not leafed through every sheet as that would take a month of Sundays (see below). Instead I've been finding all the indexes of which the are about 20+ (covering 1951-1980) and referencing from there.

Posted by: Nuvistor

Just a thought, is this a model imported from Germany or Hong Kong.

I ask because I had a few CNP190/192 type sets brought into the shop for conversion to the UK system, bought overseas and brought home when they moved back to the UK. I cannot remember the model number.

Conversion was straightforward, set the mains voltage and alter the sound. I think Hong Kong was 6 MHz but could wrong.

The vision IF could have been realigned for the wider bandwidth but I found it not needed. Pictures were excellent.

Hong Kong had 6 MHz sound. Used to see lots of oddball sets for repair that were imported to the area from there.

Evening all, thanks for the feedback so far.  here are some pics of the set which you will see looks identical to an early 70s CNP190 but as per the back cover is shown as an CNP 860. I have found a very low res schematic that shows that the set was destined for Uk / HS. where is HS? 

anyway we still have no colour and i'm guessing that the CNP 190 should yield the info on defeating the colour killer  plus a schematic. annoying as when this set was awakened from its slumber of 20 years or more it had colour but poor psu regulation and a tuning fault. now the psu is fixed the colour has disappeared. i am pretty sure i have not disturbed anything so

need to start doing some voltage and scope checks.

Well there's no doubt there, never seen that model but internally and externally looks identical to a CNP190.  Good luck with it, hope the CRT is good one .

John.

Thanks for the HK info Andy, must have just changed the voltage to 240v I am sure HK was 200v. I definitely ordered 6Mhz filters for the German ones.

Yes the 860 looks identical to the 190.

 Something that just occurred to me is that the first version of the CNP190 suffered from a lack of contrast compared to similar sized 19" UK models, this wasn't such a problem with the smaller 14" CFP470  and 17" CSP680 fitted with the same chassis. The Hitachi reps listened to our criticism and the later CNP190 had a modified decoder which produced a better picture with ample contrast. I wonder if the CNP860 could have been the later CNP190 renumbered to prevent any confusion with the manuals. Just a thought.

The CNP192 was the set we sold after the 190, the 192 had better contrast, also a different tuner and was it 6 push buttons not 4?

The CNP192 had an 8 button varicap tuner and was styled similarly to the 16" CAP160 and 18" CEP180 but the latter two retained the rotary tuner. Picture quality was superb but I don't remember if the CNP192 had a normal CRT or the low voltage uni potential focus gun type as fitted to the 190.

John.

8 buttons with a different front panel layout, yes remember now, I bought one in 1974, gave it to my father in law in 1984, only fault it ever had was a tuner fault. 

I don’t remember the CRT type, never changed one.

Sorry if this is a bit of an epic write up but I thought I would share the outcome of this little set.

1972 / 73 Hitachi CNP 860 has been sat on my bench for a few months awaiting attention, but with the recent sunshine distracting me nothing has happened to it. However today being wet was the perfect day for a bit of Tv troubleshooting fun.

This set had been stored for many years in a garage. I don’t think it had been used since the late 1980’s. However I was pleasantly surprised on removing the back cover to discover that it was clean and rust free inside. The only sign of damage was a busted aerial socket.

As it looked so clean inside and knowing how robust these early Jap colour sets were I thought I would throw caution to the wind and power it up.Encouragingly there was a rustle of EHT and after a short time a raster appeared which looked nice and bright. So feeding in a test card signal showed an undersized distorted display with no colour and frame cramping but the CRT looked good! Then about 60 seconds later a puff of smoke and the raster disappeared. Oh, crap, switch off quick and try and trace where the smoke came from. It did not take long to establish that the A1 decoupling capacitor had given up the fight for life. Replacement 0.1 uf 1kv cap brought back the original symptoms….phew!

Looking at the raster it suggested that the B+ HT rail was too low. A quick twiddle of the b+ control made no difference to the HT whichever way it was rotated so clearly the PSU was not regulating. Next to find a manual as this set is an absolute rats nest of wiring and PCBs, in fact its quite daunting at first glance. Nobody had a manual or even had reference to the model number CNP 860. The set looks identical to the more common CNP 190 and appears electrically identical too so no idea why the different model number but anyway finally got a very detailed manual from a company in the States which covered this set and several other PAL colour portable versions.

A quick look at the circuit showed the PSU to be a simple series regulator with error amplifier and not that many components either, should be easy! Wrong, I spent a good while going around in circles. Everything checked out fine with cold checks and the voltages were not too far off either. The series regulator driver transistor should have 125v bias on its base but was at 120v. The base of this transistor is also fed from a 5v taping on the mains transformer and rectified by a diode fed straight to the base. The diode had 120v one end and 0 volts the other end. Hmm no 5v ac, OC mains tx tapping maybe? Traced the wiring back which had no continuity through the winding and stumbled across a 20 mm fuse tucked away behind the mains tx. Its not shown on this diagram! Anyway it was OC but no blackened. A replacement restored the additional volts bias to the driver and everything regulated perfectly again at 120V.

I had hoped that the colour would return once the PSU was working correctly but this was not to be. The picture now filled the screen and was reasonably linier with good grey scale so we were making some progress.
The decoder is split across 3 different PCBs with lots of interconnecting wiring! The colour killer and colour matrixing is on the so called Power PCB which is not the PSU. This panel also has the frame oscillator , line oscillator and video stages contained within! The colour burst processing is done on the signals panel and the PAL processing and ref osc etc is on the little PCB under the CRT! All very disorientating!

So first to override the colour killer by linking 2 test points on the power board, this resulted in unlocked red and green floating colours. Clearly the ref osc was running but the phase loop was not keeping it locked to the transmission. A quick check on the IF board showed a good healthy colour burst signal which went on its way through a screened lead to the PAL PCB under the CRT. Removing the PAL PCB and checking the transistors in the phase loop showed the ref osc amplifier transistor was completely OC so no reference signal was being fed back to the DC amp. Anyway a replacement resorted locked colours, but still no blue. Grey scale was correct so a quick scope check showed there was no B-Y signal going to the video stage.

B-Y was coming off the Pal board ok so checked the B-Y amp transistor on the power board and bingo it was OC too. A replacement restored a nice colour picture again. Slight none linearity of the frame stage was just a electrolytic dried out plus a quick tweak of the frame biasing preset. A soak test revealed a new problem with the set occasionally drifting off tune slightly. The push button unit was not noisy so suspicion was cast on the 33v tuning volts zener. Replacement seems to have settled things down now.

So lastly a new aerial socket was fitted and 2 hours in and she is still running with a very respectable picture. Considering that this is one of Hitachis sets with instant picture at switch on as the heaters are left running I though the CRT may have suffered but thankfully not!

Well its been a journey but hopefully that’s all to report on this set and she is off to a new home soon!

Posted By: BRC 3000

Sorry if this is a bit of an epic write up but I thought I would share the outcome of this little set.

Hi Dave, 

Please don't ever feel you or anyone else for that matter, need to apologise for providing us with a wonderful write up of a TV or radio repair. This is what the forum lives and breathes for, the more such posts, the merrier I say.  What's more as there is little out there in the way of info on these sets, your post now fills that shortfall.  ? 

p.s 

You can see how alike the 860 is to the 865 here