Perdio Portarama 3 and a bit?

[thermionic]

Hello fellow TV fans.

Has anyone got / seen one of these before? Spurred on by this recent thread https://www.vintage-radio.net/forum/...d.php?t=182040, I thought I would share these photos of my set to see if any Perdio experts can shed any light on it.

The chassis and design appears to follow that of the MK3, except that this set has a 12” CRT instead of the 8.5” CRT. There also appears to be some circuit modification carried out, including a change of EHT rectifier from a DY86/87 to an EY51.

Inside the plywood cabinet sleeve, (which is slightly deeper than the MK3), there is a stamp indicating that this is a sample, and also has a serial number stamped on the chassis of 000005! Take a look also, of what looks like a ‘Simon Templar’ symbol on the cabinet!

I understood that Perdio went into voluntary liquidation whilst the MK3 was in its infancy. Could this have been a sample for a sales rep of a larger screen variant that never came to fruition?

Your thoughts please.

SimonT.

[thermionic]

And a couple of pictures of the chassis.....

[Mr Hoover]

The Vhf channel selector knob and the
single volume etc knob at the bottom are
the same type as on the portorama mk 2.

[high_vacuum_house]

Good afternoon,
Is that the one from the recent BVWS auction? I recognise the missing left hand knob!! If so it was mine for a few years. I bought it as it was under a table at a ham radio event with bits of ham radio gear piled around it and felt sorry for it!! It was one of those “round to its” that never materialised and with the move up to Belper this was one that needed to find a new home. I never got around to taking the back off and having a look around inside.

It looks a good restoration project and hopefully just the usual R’s and C’s and the cosmetics to get it working and looking good.

Glad it has gone to a good home,

Christopher Capener

[bobhowe]

Hi Simon the Perdio factory was in Sunderland and went into receivership in 1965 as you are correct . Have a look on some of the large Electrolytic capacitors if some are made by BEC they might have a month and year written on them if its 1965 could be one of the last sets made kind regards Bob

[FERNSEH]

Looks like a well developed and production ready TV set.
I assume it is dual standard.
If it had gone into full production I reckon Perdio would had a winner there.

DFWB.

[thermionic]

Originally Posted by high_vacuum_house

Good afternoon,
Is that the one from the recent BVWS auction? I recognise the missing left hand knob!! If so it was mine for a few years.......

Hi Christopher. Yes, it’s the one! I’m so glad that you managed to save it, I guess that they won’t be too plentiful. Was the MK3 that was in the same auction yours as well?

[thermionic]

Originally Posted by bobhowe

Hi Simon the Perdio factory was in Sunderland and went into receivership in 1965 as you are correct . Have a look on some of the large Electrolytic capacitors if some are made by BEC they might have a month and year written on them if its 1965 could be one of the last sets made kind regards Bob

Thanks Bob, I don’t think there are any BEC caps in there, but there are some Hunts, so I might be able to get an idea from them.

[thermionic]

Originally Posted by FERNSEH

Looks like a well developed and production ready TV set.
I assume it is dual standard.
If it had gone into full production I reckon Perdio would had a winner there.

DFWB.

Hi David.

Yes, essentially a dual standard MK3, with some modifications. Unfortunately, there is no label on the 12” CRT to identify the type. Unusually, the final anode connector is located at the bottom of the bowl rather than the side.

[thermionic]

The set has been on the bench this afternoon.


I’ve soon been stopped in my tracks......... DC fuse F4, was blown. A quick Ohms check across the main DC rail revealed a lower reading than anticipated.


The finger of suspicion pointed straight at the AU103 line output transistor. This was easily extricated from its plug in socket, and instantly surrendered to being the culprit - short circuit emitter to collector.

Not having anything suitable in my stocks, I’ve ordered one from Littlediode, so hopefully it will be a real one.....?

Cheers. SimonT.

[Mr Hoover]

Originally Posted by thermionic

The set has been on the bench this afternoon.



The finger of suspicion pointed straight at the AU103 line output transistor. This was easily extricated from its plug in socket, and instantly surrendered to being the culprit - short circuit emitter to collector.

The AU103 went in my Portorama Mk2 recently,
Not having another to hand, I tried an AD149
and it worked OK.
I must get round to ordering an AU103 but the AD149's still going strong!

[HamishBoxer]

Where is tha t warning gone about protecting the crt heaters on these? If indeed it was on the forum.

Not sure whether it is a s/c regulator that can destroy them or something else.

[Mr Hoover]

Doesn't the CRT heater (12. 6v)go straight across the incoming supply rather than being supplied from the regulator?
I have seen mentioned that if supplied from a battery the crt should have a limiting resistor as
with the combination of a low internal resistance battery and cold heater the initial current rush could blow the heater.
Wasn't it in a Rigonda where the regulator could go s/c and over run the crt heater?

[FERNSEH]

Mr. Hoover wrote: "Wasn't it in a Rigonda where the regulator could go s/c and over run the crt heater?"
Same used to happen with the BRC 1590 portable TV set. In fact any set that uses a series regulator transistor as the supply regulator.

DFWB.

[HamishBoxer]

Thank you, I will certainly take care with mine.

[slidertogrid]

Someone mentioned on here that it was the set LT potentiometer that aged and caused the LT to rise on the 1590/1 . I always used to set them for 5v on the wiper and then check the LT was correct when servicing them but I didn't know then that they could drift. I think if the series regulator went short there would be other symptoms like hum bars to give the game away.
I did hear the T-Vette could suffer with regulator failure that could blow the tube heater instantly, knowing Philips it's a wonder there wasn't an elaborate protection circuit using a Bowden cable! I have one in my collection as yet untested I think I may fit a Zener on the LT line as crowbar protection....

[Cobaltblue]

Originally Posted by Mr Hoover

Doesn't the CRT heater (12. 6v)go straight across the incoming supply rather than being supplied from the regulator?
I have seen mentioned that if supplied from a battery the crt should have a limiting resistor as
with the combination of a low internal resistance battery and cold heater the initial current rush could blow the heater.
Wasn't it in a Rigonda where the regulator could go s/c and over run the crt heater?

ISTR this is definitely the case with the Philips T-Vette the tube only has an 11V heater.

The power supply on mains can kick out around 16V if the series pass transistor fails.

Cheers Mike T

[Heatercathodeshort]

[QUOTE=slidertogrid;1392979]Someone mentioned on here that it was the set LT potentiometer that aged and caused the LT to rise on the 1590/1 ./QUOTE]

I raised this point with the 1590/91 a good few years ago. The pot rises in value with no noticeable effect on the picture. When it reaches about 14V hum bars appear on the raster stimulating a service call but it is too late.

The tube is badly over run and gives a dim picture when the fault is rectified. The cost of tube replacement was not really worth it. I used to replace the pot with a RS components high grade ceramic type. They were exactly the same size but of military quality.

It was not just the battery/mains models similar to the Perdio that suffered from PSU over volts. The Goodmans chassis with a switch mode power supply used a couple of 47uf [?] caps in the sensing circuit that would go O/C if the receiver was disconnected from the mains or there was a power cut. Re applying power usually blew the PSU up or caused the PSU to over volt with dire consequences and these were colour receivers.

Preventative maintenance helped but it was often too late. John.

[thermionic]

My replacement AU103 arrived yesterday, so, armed with a strong coffee, I set to work.

Switching on with the new Line Output Transistor fitted produced a strong 405 line whistle.........but not a hint of a raster. It was soon found that one leg of the DY51 EHT rectifier valve had come adrift from its terminal. With this resoldered, we had light!

Two issues are obvious. Lack of frame height due, more than likely from a couple of defective electrolytics, and incorrect line speed. These issues are the same on both 405 and 625 standards.

The construction of this set seems to be rather shoddy. Wires joined and taped with masking tape, and poorly soldered joints. I’m convinced this has been like this from new, as the tape is the same used elsewhere in the set. I’m sure Perdio would never have put this onto the market like this.

A date has also been found. There is a label on the scan coils of 30/11/64, which is earlier than I expected.

Does anyone have any ideas what this set was.......a MK4 in the making?


Anyway, let’s see if I can sort out the frame problems first!



Cheers. SimonT.

[Red to black]

Personally I would try to sort the Line speed issue first otherwise your new AU103 might not last long.