HMV 650 Anomaly

[stevehertz]

For sure I will seek out that Gary Tempest 650 restoration write up, but I'm just wondering how different it will be to the one he did for the Marconiphone sister model 561, they're the same set. Anyway, more information is always better. Thanks for the link David.

[stevehertz]

On the subject of crumbling insulation on wires, I take a 'need is must' approach. Some such wires, if they're short and not likely to cause a problem, I will leave alone. Others I tend to replace with new insulated wire. To add sleeving you have to unsolder one end anyway, so you may as well change the wire. However! I can see that in certain circumstances access to that other end may be difficult or impractical, so yes, sleeving will do the job.

[David G4EBT]

Originally Posted by stevehertz

For sure I will seek out that Gary Tempest 650 restoration write up, but I'm just wondering how different it will be to the one he did for the Marconiphone sister model 561, they're the same set. Anyway, more information is always better. Thanks for the link David.

Though Gary isn't a member of this forum, he does read and takes an interest in threads, and has been reading this one. He's emailed me to say that there's a further article on the 561 in the Spring 2014 BVWS Bulletin entitled: 'Another Marconi 561 Radio' which might be of interest:

https://www.bvws.org.uk/publications...olume39number1

[stevehertz]

Thanks David. For sure this set is well worthy of exposure, it's arguably one of the best AM domestic sets ever produced, that's from all standpoints - apart from its weight and bulk that is!

[cathoderay57]

I have drawn out the inter-station muting modifications to the standard HMV 650 as-found. See attached. It seems to make sense but if anybody wishes to comment then please do. Cheers, Jerry

[RoundyMooney]

I have one of Gary's dials, which he was kind enough to send me some years ago-by that chance all his "good" ones had gone, and what he sent me, with some apology, was a "second".

I have to say it looks absolutely perfect to me, which is testament to his high standards!

[stevehertz]

Originally Posted by RoundyMooney

I have one of Gary's dials, which he was kind enough to send me some years ago-by that chance all his "good" ones had gone, and what he sent me, with some apology, was a "second".

I have to say it looks absolutely perfect to me, which is testament to his high standards!

My 650 has one of Gary's dials, and I think the OP's set does too. They're a superb reproduction.

[jetstream320]

You may find that one section of the audio driver transformer primary is open circuit, it is a common fault with these. The set carries on working, but with reduced treble and more bass.
It actually sounds better like that, in my opinion. I replaced one of those transformers on my 650, and then regretted it.
Chris.

[steve102]

Originally Posted by jetstream320

You may find that one section of the audio driver transformer primary is open circuit, it is a common fault with these. The set carries on working, but with reduced treble and more bass.
It actually sounds better like that, in my opinion. I replaced one of those transformers on my 650, and then regretted it.
Chris.

I had this problem with the driver transformer in my HMV 655 and Ed Dinning did a fantastic job of re-winding it for me. I agree it could do with a bit more bass and less treble, especially when set to the high fidelity position.

Steve

[cathoderay57]

Thanks folks. All of the windings on mine check out OK; dc resistances as follows:
Primary: 300 Ohms-0-300 Ohms
Secondary: 3622 Ohms / 3622 Ohms
Measured with a digital multimeter
Cheers, Jerry

[dave walsh]

Re the inter-station "Silent Tuning" Control [posts 10*-25*] the instruction book for my Marconiphone 292 Radiogram lauds this feature and also recommends 150' of aerial wire ["high up" ] Auto muting was tried again in the early seventies on a couple of [transistor I think ?] Tuners but didn't catch on!

Dave W

[rontech]

My father's aerial system was 60 ft long at about 20 ft height. All the principal stations would close the tuning indicator petals when correctly tuned. The sets we had were RGD 625 / Marconi 564 and HMV 650

[dave walsh]

Thanks for that memory of your dad Ron. I'm reminded of "Time is a Jet Plane- it moves too fast! Oh but what a shame, if all we had can't last" [Bob Dylan's divorce album "Blood On The Tracks"-pun intended!]. After decades of the endless tour, he's currently still out there as Frank Sinatra but suddenly, with a 2024 stop date to his "Rough and Ready" gigs. Maybe he's just anticipating the end [at 81] with better and better versions of a song called "Key West [is the place to be!] but Florida isn't doing so well at the moment for retirement is it? .

Dave

[cathoderay57]

For those of you still interested, the project is progressing hopefully to power-up next week. Since the original question topic re:silent tuning circuit is now resolved (thanks to Steve102) I won't be posting any more in this thread but will compile a success story soon. Thanks to all who have contributed. Cheers, Jerry

[RoundyMooney]

Thanks Jerry-looking forward to that. As jetstream320 pointed out, the interstage trafo is a weak point on these as well. In fact Ed Dinning was kind enough to take mine on and rewind it for an extremely modest fee.