Roberts R25 radio problem. - UK Vintage Radio Repair and Restoration Discussion Forum

Mgmaudio · 23rd May 2023, 7:22 am

I have one of these radios in excellent condition, except for the fact the ON/OFF switch is faulty.

It has to be held down to make the radio work.

Two questions:

Is the switch, or an equivalent, available?
If so, how do you remove the radio chassis from the cabinet ?

I cannot see a way to begin this process.

Thank you in anticipation.

agardiner · 23rd May 2023, 9:04 am

I don't have the service sheet so cannot be sure, but looking at a photo of one, it looks like one of the series where the chassis is held in by screws under the handle? You should be able to see that by looking in the set from the underside.

If so, the handle will unclip from its fixings by pushing it downwards, and once removed the screws will be revealed.

Paul_RK · 23rd May 2023, 9:13 am

I don't think the handle need be taken off, the screws are accessible when it's folded down. To remove the chassis you'll also have to remove the screw that retains the telescopic aerial, and disconnect the leads to loudspeaker and power supply. If it hasn't been out for years it may be a little stuck to the cabinet, but there's nothing else holding it in place.

Paul

simpsons · 23rd May 2023, 9:41 am

First, getting the chassis out of the cabinet.

The Service Manual is available on the internet and is a must, as there are several screws to remove before removing the chassis by easing it up from the top of the set. The power supply removal is also explained.

Next, the on/off switch. This model has a loudness tap on the volume control which the replacement will need to have. This is a 100k pot and used on many Roberts sets. Should it need replacing, a "parts wanted" post on this site will help you find one.

Good luck

Chris

David G4EBT · 23rd May 2023, 9:50 am

The service data for the R25 isn't on the Forum DVDROM, but if the R25 is similar to the R24, I guess it has a bank of four individual push-button switches: LW, MW, VHF, & On/Off. If so, the waveband switches will be interlocking, so that if for example, the switch for LW is pressed in, and you then press VHF, the VHF switch will latch and the LW one will unlatch.

The On/Off switch will, I think, be independent of the waveband switches, and will latch when pressed on and unlatch when pressed off. It may be that the little spring which causes it to latch has failed, but on some styles the spring is external and may have come out of its notch and could maybe refitted, though the springs are often internal.

Roberts Radio do supply a limited range of replacement parts for some models, but I've just checked and you're out of luck with the R25 I'm afraid:

https://www.robertsradiotechnical.co...tsRequest.aspx

Several companies supply similar PCB-mounted switches, but the pins would need to exactly match the spacing of yours and the dimensions of the square shaft would need to be the same. Here are some examples of what the style of switch that you need looks like:

https://www.switchelectronics.co.uk/...on-switch-dpdt

https://uk.rs-online.com/web/p/push-...itches/7582091

https://www.rapidonline.com/r-tech-7...waAgcIEALw_wcB

It terms of gaining access to remove the chassis, as often as not, if you remove the bottom panel, there will be a screw at each end of the chassis which need to be removed, and a screw which holds the telescopic antenna. I've attached an annotated picture of a Roberts R505 radio, which is an altogether different model, though I guess a similar cabinet style, which shows how to remove the chassis. When you've taken out the screws and disconnected the speaker, you need to push the chassis upwards, which might need some pressure, but don't be tempted to lever it out from the top or you'll risk damaging the front panel and trim.

I hope that might help a bit, but other forum members with specific experience of the R25 might be able to help further.

Good luck with it.

Station X · 23rd May 2023, 9:51 am

Quote:

Originally Posted by simpsons

The Service Manual is available on the internet...

Chris

Any chance of a link to the service manual? It's not available from VRSD.

Paul_RK · 23rd May 2023, 9:51 am

Apologies, my post above may be misleading - I was looking at the R24 manual, and haven't had access to one for the R25. Probably not very different, as a photo of the R25 shows the same arrangement with chassis-fixing screws on the cabinet sides and revealed when the handle is swung down.

Paul

Andy 1964 · 23rd May 2023, 9:53 am

Very similar to my R23. The on/off switch is on the wave change bank, independent of the volume control. Most likely just dirty, along with the wave band switches, give it a good dose of contact cleaner, and then operate all the switches. Fluff can get into the headphone socket, clean that. The PSU had some electrolytic caps that were half of their stated value, these were replaced before an AC power up, so just use the battery to check for signs of life.

David G4EBT · 23rd May 2023, 9:59 am

Quote:

Originally Posted by Station X

Quote:

Originally Posted by simpsons

The Service Manual is available on the internet...

Chris

Any chance of a link to the service manual? It's not available from VRSD.

https://archive.org/details/manual_R25_SM_ROBERTS

PDF:

https://ia902307.us.archive.org/8/it...SM_ROBERTS.pdf

Andy 1964 · 23rd May 2023, 10:25 am

Just had a look at my R23, chassis is on my bench. The latching mechanism is clearly visible, and if anything is broken it will be obvious. Could be grunge in the mechanism preventing the latch engaging. Observe the sideways movement bar, which operates the latches.

Mgmaudio · 23rd May 2023, 6:54 pm

I managed to get the R25 apart and it’s definitely the on/off switch.
There is another problem, in that the PP9 connector is broken on one terminal.
Easy enough to replace.

I don’t think I will attempt to replace the switch.
I have more than enough radios...
If someone wants it, they can have it for the price of the new PP9, plus postage.
It is in good condition.

23rd May 2023, 7:22 am	#1
Mgmaudio Tetrode Join Date: Dec 2013 Location: Witney, Oxfordshire, UK. Posts: 73	Roberts R25 radio problem. I have one of these radios in excellent condition, except for the fact the ON/OFF switch is faulty. It has to be held down to make the radio work. Two questions: Is the switch, or an equivalent, available? If so, how do you remove the radio chassis from the cabinet ? I cannot see a way to begin this process. Thank you in anticipation. Last edited by Mgmaudio; 23rd May 2023 at 7:29 am. Reason: Spelling

23rd May 2023, 9:04 am	#2
agardiner Octode Join Date: Sep 2020 Location: Thetford, Norfolk, UK. Posts: 1,741	Re: Roberts R25 radio problem. I don't have the service sheet so cannot be sure, but looking at a photo of one, it looks like one of the series where the chassis is held in by screws under the handle? You should be able to see that by looking in the set from the underside. If so, the handle will unclip from its fixings by pushing it downwards, and once removed the screws will be revealed.

23rd May 2023, 9:13 am	#3
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,256	Re: Roberts R25 radio problem. I don't think the handle need be taken off, the screws are accessible when it's folded down. To remove the chassis you'll also have to remove the screw that retains the telescopic aerial, and disconnect the leads to loudspeaker and power supply. If it hasn't been out for years it may be a little stuck to the cabinet, but there's nothing else holding it in place. Paul

23rd May 2023, 9:41 am	#4
simpsons Octode Join Date: Feb 2007 Location: Harrow, London, UK. Posts: 1,493	Re: Roberts R25 radio problem. First, getting the chassis out of the cabinet. The Service Manual is available on the internet and is a must, as there are several screws to remove before removing the chassis by easing it up from the top of the set. The power supply removal is also explained. Next, the on/off switch. This model has a loudness tap on the volume control which the replacement will need to have. This is a 100k pot and used on many Roberts sets. Should it need replacing, a "parts wanted" post on this site will help you find one. Good luck Chris

23rd May 2023, 9:50 am	#5
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,761	Re: Roberts R25 radio problem. The service data for the R25 isn't on the Forum DVDROM, but if the R25 is similar to the R24, I guess it has a bank of four individual push-button switches: LW, MW, VHF, & On/Off. If so, the waveband switches will be interlocking, so that if for example, the switch for LW is pressed in, and you then press VHF, the VHF switch will latch and the LW one will unlatch. The On/Off switch will, I think, be independent of the waveband switches, and will latch when pressed on and unlatch when pressed off. It may be that the little spring which causes it to latch has failed, but on some styles the spring is external and may have come out of its notch and could maybe refitted, though the springs are often internal. Roberts Radio do supply a limited range of replacement parts for some models, but I've just checked and you're out of luck with the R25 I'm afraid: https://www.robertsradiotechnical.co...tsRequest.aspx Several companies supply similar PCB-mounted switches, but the pins would need to exactly match the spacing of yours and the dimensions of the square shaft would need to be the same. Here are some examples of what the style of switch that you need looks like: https://www.switchelectronics.co.uk/...on-switch-dpdt https://uk.rs-online.com/web/p/push-...itches/7582091 https://www.rapidonline.com/r-tech-7...waAgcIEALw_wcB It terms of gaining access to remove the chassis, as often as not, if you remove the bottom panel, there will be a screw at each end of the chassis which need to be removed, and a screw which holds the telescopic antenna. I've attached an annotated picture of a Roberts R505 radio, which is an altogether different model, though I guess a similar cabinet style, which shows how to remove the chassis. When you've taken out the screws and disconnected the speaker, you need to push the chassis upwards, which might need some pressure, but don't be tempted to lever it out from the top or you'll risk damaging the front panel and trim. I hope that might help a bit, but other forum members with specific experience of the R25 might be able to help further. Good luck with it. Attached Thumbnails __________________ David. BVWS Member. G-QRP Club member 1339. Last edited by David G4EBT; 23rd May 2023 at 10:00 am.

23rd May 2023, 9:51 am	#7
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,256	Re: Roberts R25 radio problem. Apologies, my post above may be misleading - I was looking at the R24 manual, and haven't had access to one for the R25. Probably not very different, as a photo of the R25 shows the same arrangement with chassis-fixing screws on the cabinet sides and revealed when the handle is swung down. Paul Last edited by Paul_RK; 23rd May 2023 at 9:57 am.

23rd May 2023, 9:53 am	#8
Andy 1964 Pentode Join Date: Jan 2021 Location: Hinckley, Leicestershire, UK Posts: 119	Re: Roberts R25 radio problem. Very similar to my R23. The on/off switch is on the wave change bank, independent of the volume control. Most likely just dirty, along with the wave band switches, give it a good dose of contact cleaner, and then operate all the switches. Fluff can get into the headphone socket, clean that. The PSU had some electrolytic caps that were half of their stated value, these were replaced before an AC power up, so just use the battery to check for signs of life.

23rd May 2023, 10:25 am	#10
Andy 1964 Pentode Join Date: Jan 2021 Location: Hinckley, Leicestershire, UK Posts: 119	Re: Roberts R25 radio problem. Just had a look at my R23, chassis is on my bench. The latching mechanism is clearly visible, and if anything is broken it will be obvious. Could be grunge in the mechanism preventing the latch engaging. Observe the sideways movement bar, which operates the latches.

23rd May 2023, 6:54 pm	#11
Mgmaudio Tetrode Join Date: Dec 2013 Location: Witney, Oxfordshire, UK. Posts: 73	Re: Roberts R25 radio problem. I managed to get the R25 apart and it’s definitely the on/off switch. There is another problem, in that the PP9 connector is broken on one terminal. Easy enough to replace. I don’t think I will attempt to replace the switch. I have more than enough radios... If someone wants it, they can have it for the price of the new PP9, plus postage. It is in good condition.