HMV2352 Radiogram - UK Vintage Radio Repair and Restoration Discussion Forum

Herald1360 · 5th Nov 2021, 7:34 pm

I've got one of these on the bench just now (living room floor to be precise). It's a Repair Cafe job that was delivered to me this morning.

Fault was described as loud hum and no output. This was indeed the case, but in addition I found the tuning drive was seized solid.

With the chassis out, turning on briefly resulted in hum but only on one channel. The main smoothing can and metal rectifier checked out OK but inspection of the PCB revealed a sprinkling of black Callins, two of which had blown their tops off. The whole lot were evicted (surprisingly only the topless ones were actually dead) and replaced with a selection of new parts. Turning on again revealed a lack of hum and some quiet hiss- more like it! After a disappointing hum check with finger on the PU inputs, a bit of RTFM revealed that the volume control wasn't coaxial with the on/off switch and was in fact turned right down

Two channels now hummed nicely when prodded

Now to have a go at that tuning drive- looks like solidified grease on the slow motion capacitor drive......

Edward Huggins · 6th Nov 2021, 10:23 am

Good to see this - I note the FM Dipole on the underside of the cabinet. Weren't these Thorn chassis so flimsily made? Just about every one of the Thorn range of this period (HMV, Marconiphone, Ferguson, Ultra) used the same recipe of basic BSR deck, very similar AM/FM chassis and two 8" x 5" speakers. Let us know how you get on!

Herald1360 · 7th Nov 2021, 2:49 am

The solidified grease put up a serious fight. The tuning gang, complete with FM tuner head had to be removed and the 100W iron applied to get it to move but in the end the shaft complete with its bush had to be twisted out of the gang body to allow the shaft to be drifted out of the bush and the old grease scraped off.

Refitting the tuner head assembly enabled the radio side to be checked- it worked fine, but when restringing the pointer drive it became clear that the relative positions of the shaft and its gear and the tuning gang itself were critical to the pointer drive since the cord drum was keyed to the D of the shaft. A further stripdown and reassembly in the correct alignment was required.

The record playing side threw up a final issue- the stylus tip was bent

Luckily this responded to some careful tweaking under the magnifier with fine nosed pliers and the whole system now worked OK.

HiFi it ain't, 2Wpc and 8x5 elliptical speakers in open enclosures at each end give a noticeably "boxy" tone but it's probably as good as it ever was.

5th Nov 2021, 7:34 pm	#1
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	HMV2352 Radiogram I've got one of these on the bench just now (living room floor to be precise). It's a Repair Cafe job that was delivered to me this morning. Fault was described as loud hum and no output. This was indeed the case, but in addition I found the tuning drive was seized solid. With the chassis out, turning on briefly resulted in hum but only on one channel. The main smoothing can and metal rectifier checked out OK but inspection of the PCB revealed a sprinkling of black Callins, two of which had blown their tops off. The whole lot were evicted (surprisingly only the topless ones were actually dead) and replaced with a selection of new parts. Turning on again revealed a lack of hum and some quiet hiss- more like it! After a disappointing hum check with finger on the PU inputs, a bit of RTFM revealed that the volume control wasn't coaxial with the on/off switch and was in fact turned right down Two channels now hummed nicely when prodded Now to have a go at that tuning drive- looks like solidified grease on the slow motion capacitor drive...... Attached Thumbnails __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

6th Nov 2021, 10:23 am	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,335	Re: HMV2352 Radiogram Good to see this - I note the FM Dipole on the underside of the cabinet. Weren't these Thorn chassis so flimsily made? Just about every one of the Thorn range of this period (HMV, Marconiphone, Ferguson, Ultra) used the same recipe of basic BSR deck, very similar AM/FM chassis and two 8" x 5" speakers. Let us know how you get on! __________________ Edward.

7th Nov 2021, 2:49 am	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: HMV2352 Radiogram The solidified grease put up a serious fight. The tuning gang, complete with FM tuner head had to be removed and the 100W iron applied to get it to move but in the end the shaft complete with its bush had to be twisted out of the gang body to allow the shaft to be drifted out of the bush and the old grease scraped off. Refitting the tuner head assembly enabled the radio side to be checked- it worked fine, but when restringing the pointer drive it became clear that the relative positions of the shaft and its gear and the tuning gang itself were critical to the pointer drive since the cord drum was keyed to the D of the shaft. A further stripdown and reassembly in the correct alignment was required. The record playing side threw up a final issue- the stylus tip was bent Luckily this responded to some careful tweaking under the magnifier with fine nosed pliers and the whole system now worked OK. HiFi it ain't, 2Wpc and 8x5 elliptical speakers in open enclosures at each end give a noticeably "boxy" tone but it's probably as good as it ever was. Attached Thumbnails __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O