Share:
Notifications
Clear all

HMV 2715 (3500)

 
The_Teleman
(@the_teleman)
Active V-Ratter Registered

now most people on this forum seem to love these sets , me on the other hand never could take to them they seem to be like marmite sets you either love them or hate them

the set in question is a HMV 2715 fitted with the thorn 3500 chassis , now back in my tv days we used to service theses sets as well as many other makes including Decca, ITT & GEC , The odd other make Telpro & Teleton came up from time to time of course I’m going back 35+ years & the old grey matter as well as the eye sight are not as they were.

The only reason I acquired this set was I liked the cabinet style & the price was good too ,having got the set home I had a quick look round the set all looked complete even though the power supply looked a bit got at

BDE2E61D 51B2 4C7D A69D 9F09DE3FE82D

The rest of the set looked tidy

E7843275 67D5 4563 B7E0 4003015A6508
CB0B1C19 DB1D 46BA 8866 6B0048FCE8AC

Testing the crt was another thing I done if that had been duff I wouldn’t have gone any further but it tested 100% & it’s a thorn new life according to the label it was fitted on 31/12/81 so not bad so far

Chris

ReplyQuote
Topic starter Posted : 10/06/2019 1:33 pm
Lloyd
(@lloyd)
Noble V-Ratter Registered

Nice find, I have the HMV 2711, big beast 26” with doors, I didn’t get a stand with mine though.

Regards

Lloyd

ReplyQuote
Posted : 10/06/2019 6:58 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Apart from that abomination of a C609 replacement it does looks to be in good shape. It would be a good idea to cast your eye over the connections on the mains transformer, there should be one tag with no connections made. Connecting the CRT heater to this vacant tag enabled sets to be run on mains as low as 200V and some used this to give a poor CRT a little boost when on full 240V mains. If the heaters weren't returned to the correct tag a replacement would have a short life.

Are those high wattage resistors in the RGB output stage original? I have seen later video boards fitted with them from the factory instead of a thick film unit, possibly due to a supply shortage.

ReplyQuote
Posted : 10/06/2019 8:19 pm
The_Teleman
(@the_teleman)
Active V-Ratter Registered

The next step was to tackle the power supply

most of the electrolytic caps are either leaking or totally out of spec so a total recap was in order, the only good cap was the main smoother

next was the line time base this also needs a re cap I was hoping this wasn’t going to be the case for every panel but it was

the line panel & power supply done I thought I would give it some power , the power supply was running but no EHT checks revealed nothing apart from the fact the the line driver wasn’t working , now this was checked but nothing seemed wrong I even took out the driver transistor & tested it but that tested fine so after some serious head scratching I decided to just replace the line drive transistor , success ! Now why? Would it test ok but just not work but anyway the set now runs

F22E5649 8586 4A53 94F7 2F2F5293D4B2

no colour & he grey scale was changing both faults are due to faulty electrolytics on the video & decoder panels

BB699C2D 2629 4DBD B4E2 A27AAD7BB441

Now I know the set is working but it could do with some further TLC sadly it may have to wait a while as my son is moving house & time will be a bit short for a while

chris

ReplyQuote
Topic starter Posted : 11/06/2019 12:08 pm
Lloyd and PYE625 liked
The_Teleman
(@the_teleman)
Active V-Ratter Registered
Posted by: Jayceebee

Apart from that abomination of a C609 replacement it does looks to be in good shape. It would be a good idea to cast your eye over the connections on the mains transformer, there should be one tag with no connections made. Connecting the CRT heater to this vacant tag enabled sets to be run on mains as low as 200V and some used this to give a poor CRT a little boost when on full 240V mains. If the heaters weren't returned to the correct tag a replacement would have a short life.

Are those high wattage resistors in the RGB output stage original? I have seen later video boards fitted with them from the factory instead of a thick film unit, possibly due to a supply shortage.

Hi John , the RGB panel looks original there are holes in the board for a thick film unit but has never been used

ReplyQuote
Topic starter Posted : 11/06/2019 12:12 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Looks like you've a corker there Chris ? . Very late in the 3500's life another thick film unit was employed, this time a hybrid type in the frame stage. Very similar style to those used in the 4000 it contained the oscillator and drive circuitry retaining the original output stage. Wonder if anyone has one in their collection?

ReplyQuote
Posted : 11/06/2019 9:31 pm
glenz75
(@glenz75)
Trusted V-Ratter Registered

It would seem you've a good candidate there for restoring. These chassis were cloned in New Zealand under the Thorn and AWA brands and known as the "TX574" and there was also a love/hate relationship with the tech's as well ( most probably hated them!) We had 26 inch console as a family set which got nursed into the 1980's when it was retired and a National Quintrix replaced it (and never broke down, the CRT wore out!) I'd love to get my hands on of these 3500's but alas they're pretty much extinct in these parts now.

ReplyQuote
Posted : 21/06/2019 1:17 am
Till Eulenspiegel
(@till)
Famed V-Ratter Registered

I never had the  HMV 2715 in my rental fleet, the majority of the 3500 series sets were the Alba models TC2222 and TC2223. I think I've got the model numbers right.  After 1975 when I started buying Thorn sets direct  from the manufacturer and the most popular set for obvious reasons was the HMV 2725 the model that had the 8800 series chassis.  It was worth paying a little extra to get that beautiful wood cabinet.

Sadly in 1977 when Thorn decided not to renew the licence from EMI to use the HMV and Marconi brands the most popular HMV 22" colour TV set was no longer available.

Later on Thorn Electrical Industries merged with EMI to form Thorn-EMI ltd.

                                                           Till Eulenspiegel.

ReplyQuote
Posted : 21/06/2019 5:27 pm
Tazman1966
(@tazman1966)
Reputable V-Ratter Registered

Lovely set there Chris. I really liked that style of cabinet, even the tiny version fitted with the 17" 8000A chassis

ReplyQuote
Posted : 12/07/2019 11:56 am
The_Teleman
(@the_teleman)
Active V-Ratter Registered

@tazman1966

Thanks Taz the set is being moved on to Gary (colourmaster) shortly I’ve done a swap for a couple of GEC solid state sets

at least I know it’s going to a good home

Chris

ReplyQuote
Topic starter Posted : 15/07/2019 12:14 pm