UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Closed Thread
 
Thread Tools
Old 3rd Jul 2014, 9:26 am   #21
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Hi Mike

All of this is a massive learning curve for me, thanks for your assistance too!

Graham
sooperrio is offline  
Old 3rd Jul 2014, 10:06 am   #22
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

Quote:
Originally Posted by Cobaltblue View Post
There's a good page on recognising capacitor types here
Great link Mike, thanks. And I agree with every word he says!
stevehertz is offline  
Old 5th Jul 2014, 11:47 am   #23
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Hi All

Can I just check something with you regarding buying replacement capacitors, please?

As an example, wiping off the gunge from an old capacitor, I can read "0.01 MFD 500VDC".
If I am buying a replacement, looking at the Cricklewood website, I would be purchasing Part No.: CFH10NH
http://www.cricklewoodelectronics.co...me.php?cat=151

Or do I need to be worried that my old capacitor states "500 VDC", the replacement "630V"?

Once again, any advice would be appreciated.

Thank you!
sooperrio is offline  
Old 5th Jul 2014, 12:42 pm   #24
westcliff
Hexode
 
westcliff's Avatar
 
Join Date: Jan 2011
Location: Essex, UK
Posts: 396
Default Re: Ambassador 545

You should replace the old capacitors with new ones of the same or higher voltage ratings, so 630V is fine.

Gus.
westcliff is offline  
Old 5th Jul 2014, 12:44 pm   #25
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Thank you!
sooperrio is offline  
Old 5th Jul 2014, 5:33 pm   #26
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

Cricklewood are a good company to deal with. I don't know about prices (they seem reasonable to me?) but they're quick and efficient and they carry the style and spec of components that are used in vintage sets. I've used them several times now, don't bother looking at Maplin etc etc.
stevehertz is offline  
Old 5th Jul 2014, 6:54 pm   #27
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Hello,

Me again!

May I pick your brains on something else, please?

Just struggling to identify some capacitors, and for that matter, resistors.
Looking at the system data, just can't quite manage my way around a particular area.

Please could you help me with the attached photo?

There are a couple of tan coloured, flat components with the legend "LE" or "LEM".
How can I be sure of the Voltage required? (I am guessing they are capacitors).

Also, the flat brown component in the centre, again, how do I ID the nf and voltage please? I can't read anything on the item.

Finally, I think I am missing some capacitors, when referring to the service data. Are the small, stripy fella's resistors or capacitors, please!?

Much obliged!
Attached Thumbnails
Click image for larger version

Name:	Capacitor ID.jpg
Views:	150
Size:	73.6 KB
ID:	94812  
sooperrio is offline  
Old 5th Jul 2014, 7:30 pm   #28
westcliff
Hexode
 
westcliff's Avatar
 
Join Date: Jan 2011
Location: Essex, UK
Posts: 396
Default Re: Ambassador 545

These flat tan coloured capacitors don't normally need to be replaced. The tubular wax-covered paper ones on the other hand are usually replaced as they absorb moisture and get leaky. Some people replace all of the tubular ones when restoring a set; some replace only the ones which can cause damage if they fail.

The small stripey things are resistors and the brown component will have some sort of code on it, perhaps coloured dots.

Gus.
westcliff is offline  
Old 5th Jul 2014, 8:11 pm   #29
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Thank you, Gus.

May I just check something else, please, guys?
So sorry for being a pain.

On the attached image, can you see the big, black circular object, pinned to the chassis toward the top of the image?
Am I correct in assuming this is an Electrolytic Capacitor, similar to the Philips type, mentioned elsewhere on this website?
Also, the brown, flat, object component bang in the middle (hidden by a pinky/orange wire), it either reads 10C or 100, is this a capacitor, please?

Thanks once more!
Attached Thumbnails
Click image for larger version

Name:	Capacitor ID 2.jpg
Views:	134
Size:	121.5 KB
ID:	94818  
sooperrio is offline  
Old 5th Jul 2014, 9:28 pm   #30
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,526
Default Re: Ambassador 545

The blackish thing under the clip does look like an electrolytic. The square black one looks like another silver mica type- probably OK.
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is online now  
Old 5th Jul 2014, 10:32 pm   #31
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

I'd undo the clip so as to release the cap, then remove that tape and read off the value of the cap. Someone has added the tape most probably because it was a loose fit replacement. Less likely is that the tape is insulating the can (negative connection) from the chassis. You'd need to refer to the circuit diagram to see if that cap is connected to earth (chassis) or not.
stevehertz is offline  
Old 5th Jul 2014, 11:40 pm   #32
Cobaltblue
Moderator
 
Cobaltblue's Avatar
 
Join Date: Dec 2010
Location: Exeter, Devon and Poole, Dorset UK.
Posts: 6,822
Default Re: Ambassador 545

Hi Graham

It looks as if this capacitor is insulated from the chassis and is C26 (8uF) on the ERT diagram.

This is part of the AVC delay circuit decoupling.

You should find that one lead of this capacitor (the negative end) goes off to the lampholder.

If you replace this capacitor you will need to ensure that the replacement is also insulated from the Chassis and rated for at least 350V DC (450 would be better) If you cant get 8uF 10 uF will be fine.

Cheers

Mike T
__________________
Invisible airwaves crackle with life or at least they used to
Mike T BVWS member.
www.cossor.co.uk
Cobaltblue is online now  
Old 6th Jul 2014, 5:50 am   #33
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Hi Everyone
I am so grateful to you all, thanks for sharing your knowledge!

Quote:
Originally Posted by Cobaltblue View Post
If you replace this capacitor you will need to ensure that the replacement is also insulated from the Chassis and rated for at least 350V DC (450 would be better)
Would this be a suitable replacement?

Part No.: 8A450
http://www.cricklewoodelectronics.co...me.php?cat=162

And how would I insulate it from the chassis?
sooperrio is offline  
Old 6th Jul 2014, 3:45 pm   #34
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

That cap would be fine, but what is the voltage on the old one? it looks like it could be a radially leaded cap? (both leads at one end). If that's the case you may get an 8uF one with a lower voltage (if yours is lower than 450V) that is radial, and so make replacement a tad easier. Whatever, either way, a new electrolytic will be already insulated with a thin plastic sleeve, however I'd put a few wraps of insulating tape around it to stop the clip cutting through and making contact with the metal can. The other thing is, the diameter of the new cap may well be quite a bit less than the clip. If it's not much, just increase the thickness of the cap with tape, alternatively bend the clip so as to make it contact the new cap, or a combination of both. If the cap leads look like they may touch something, then put some sleeving on them to insulate them. You can use the old sleeving if there is any, it's fine.

Last edited by stevehertz; 6th Jul 2014 at 3:52 pm.
stevehertz is offline  
Old 6th Jul 2014, 7:08 pm   #35
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Thank you, Steve, great advice.
(The old capacitor is rated 450V and has a lead coming out of each end).

I'll actually start replacing the old capacitors and resistors very shortly, but, looking well ahead, I am really worried about the 'power unit' - it looks badly corroded.
Hope you all don't mind me picking your brains again!

However, if my questions suddenly stop coming, you may as well take it I have blown myself up.

Thank you all once more.
sooperrio is offline  
Old 6th Jul 2014, 7:27 pm   #36
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

1) In that case, the 8uF 450V Cricklewood cap you identified is the one to go for.

2) Ok, give us a photo of what you perceive as being 'the power unit'. Circle around the 'unit' in a photo and we can take it from there.

In general, components in vintage wireless sets - such as transformers, inductors, IF cans, speakers and valves - can often look grotty, but mostly they're in good serviceable condition. Conversely, others, like the wax paper and electrolytic capacitors you're changing are more often that not, duff. So, let's identify first of all what component(s) you're referring to and as I say, we can take it from there.
stevehertz is offline  
Old 7th Jul 2014, 2:58 pm   #37
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Hi Steve

Here is a picture of what I am taking to be the 'power unit' (should I call it a transformer??), it is the black unit, slap bang in the middle of the photo with wires coming out from it!

Thanks for any advice you can offer,

Graham
Attached Thumbnails
Click image for larger version

Name:	Power Unit.jpg
Views:	130
Size:	100.1 KB
ID:	94877  
sooperrio is offline  
Old 7th Jul 2014, 5:35 pm   #38
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,809
Default Re: Ambassador 545

Yes that's the mains transformer. It takes mains voltage at 230V AC and transforms it down to various other, lower AC voltages that are needed by the set. I mean, those overheated resistors suggest a problem somewhere along the line with that set. And your mum told you about that smoke the last time it was used. The smoke could have been from the transformer, it could have been from elsewhere. Also, the transformer could have got very hot due to a fault elsewhere, and emitted smoke as a result, but still survived. If you have the necessary meter and data (resistance readings of the various transformer windings) then you could attempt to measure the transformer windings and see what it tells. Personally I think it may be easier for you to replace those caps etc and then fire it up. Ok, if the trannie is no good, then you've 'wasted' money on the parts. But, that's the easier route if you're unsure how to evaluate that trannie. But old transformers don't always look good, they're old gnarly things often!
stevehertz is offline  
Old 7th Jul 2014, 6:49 pm   #39
sooperrio
Retired Dormant Member
 
Join Date: Jun 2014
Location: York, North Yorkshire, UK.
Posts: 61
Default Re: Ambassador 545

Thanks Steve,

I will proceed with the easier route, and, if things don't work out, I haven't spent a massive amount of money on parts yet.

I am sorry to have to ask for help once more, but I need to replace three resisters that have over heated.
On the system data, one is rated 220ohms, the other two, which are daisy-chained together, 440ohms each.
I am once again presuming, (eek), that these are the replacements I need:
http://www.cricklewoodelectronics.co...me.php?cat=509
However, no idea what the wattage refers to on the Cricklewood page, and if I cannot find a resistor with the exact ohms value as the overheated ones, do I go for higher or lower value resistors?

Once again, thanks to anyone who can advise!
sooperrio is offline  
Old 7th Jul 2014, 7:21 pm   #40
'LIVEWIRE?'
Rest in Peace
 
'LIVEWIRE?''s Avatar
 
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
Default Re: Ambassador 545

Personally, I wouldn't have thought that 14 Watt resistors were needed in a unit of this type. Old resistors are larger than their modern equivalents, and, whilst I'm not familiar with this model, I would have thought that 2 watt resistors would be adequate (correct me if I'm wrong). As to resistor values, 220 Ohms is a standard 'preferred value', but 440 ohms isn't, 470 ohms is the nearest available to this.
'LIVEWIRE?' is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:20 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.