Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? - UK Vintage Radio Repair and Restoration Discussion Forum

Okto1984 · 7th Jul 2015, 8:57 pm

My mixer could really benefit from being taken apart, cleaned inside and repainted. While I'm doing this, I'm planning to replace the motor brushes if needed and the capacitors (40+ year old RIFAs are probably bad news), but what I'm unsure about is the choke and resistor? The motor repair kits on eBay contain these parts, but my motor isn't broken, just old. I know nobody can say for certain how it may last, but are these parts particularly common failures, and if they do happen to break, would it cause any other damage? I'm considering this in detail as my cheapest source for the resistor is £15 at the moment, so unless I find it cheaper, it would be a big chunk of my budget. I want to do it properly, but not to spend money on parts that might be perfectly good for another 40 years. Any thoughts about the resistor, or in general, would be much appreciated?

HG MICKE · 8th Jul 2015, 9:45 am

The 100nf capacitor normally needs replacing, the replacement type is a RIFA PMR209MC RC unit which incorporates a 470R resistor. When this cap fails it blows the choke and the 450R resistor.
If the resistor and choke are intact they do not need changing. The carbon brushes would probably need replacing. However the MOST important thing to change and is frequently overlooked are the rubber feet - these allow airflow through the motor assemby and it is overheating that causes most failures.

Colin

FIXITNOW · 8th Jul 2015, 12:53 pm

I have some pdf's that came with the repair kit I fitted, send me your email address if you want them.
Vince

Okto1984 · 8th Jul 2015, 8:31 pm

Hi Colin, thank you for explaining about this capacitor/resistor, that's really helped. Do you happen to know if it's in series or parallel however? I couldn't tell from looking at it. As for the feet, I replaced mine a while back as they'd vanished by the time I got the mixer. New feet also stop it walking around the counter while kneading bread dough.

Hi Vince, thank you for your offer to send the files, I think that could help a lot as I still have some uncertainties about this mixer. I'll PM you.

I managed to take it apart today, and it's a one capacitor motor. Looks like the big grey cylinder capacitor (likely some kind of electrolytic?) is replaced in the kits with a smaller film capacitor. So they weren't fitted with RIFAs originally it seems. I made some other progress too, I fixed the damaged mains lead by cutting off the worn section and rewiring it in to the base of the mixer, and I found a way to revive the original paint. I was cleaning it up and happened to try a can of Servisol De-flux 160 on a stubborn bit of cake splatter, and something rather surprising happen when I wiped the paint. It took off the chalky oxidised surface and suddenly the area I'd cleaned looked new again. Cleaning with detergent had not done this, so it must be something to do with the solvents in the flux cleaner. A little bit of the orange paint had rubbed off on the tissue, but it wasn't very much, and the results are excellent. I just sprayed it on, quickly polished in circles with a tissue, and it looks great. Nice, bright and shiny. As this process is slightly wearing away the paint however, I'd do it once to a kenwood with tired paint to revive it, but not as everyday cleaning.

I think a new capacitor and brushes should be all that's needed now.

HG MICKE · 9th Jul 2015, 8:21 am

The resistor is parallel to the capacitor and is actualy built in the cap package, This capacitor replaces the large metal cased cap.
RS stock the cap,If you can not get one I have a couple in stock.

Colin

Okto1984 · 9th Jul 2015, 3:11 pm

Hi Colin, thank you for explaining this. It does make sense, I'm just used to newer stuff (about 1980 onwards), so this older style capacitor is an unusual thing for me. Also, thank you for your offer to help with obtaining the capacitor. I have however bought one on eBay yesterday. RS are a fair bit cheaper per capacitor, but only sell them in multiples of five.

Okto1984 · 11th Jul 2015, 7:57 pm

I did the carbon brushes today. The old ones were quite worn. It was very fiddly though, the spring kept curling around and was in danger of being crushed when I tightened the plastic cap. Much more difficult than the brushes I've encountered before in washing machines where the spring is contained inside a metal case. I'm a little concerned the spring isn't in the right place, but I can't see inside once it's assembled. Seems to work well however, and sounds much better now too.

Okto1984 · 25th Jul 2015, 4:52 pm

The mixer is finished now. It got a bit delayed, but the capacitor (RIFA PMR209MC RC) got here in the end, and was simple enough to fit.

For anyone who is curious, the carbon brushes aren't so difficult as I thought at first. The secret seems to be to only tighten the plastic caps until they're flush with the case, then the carbon brush and spring puts itself in the right place. I found this by carefully removing them again and looking at how they were placed.

7th Jul 2015, 8:57 pm	#1
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? My mixer could really benefit from being taken apart, cleaned inside and repainted. While I'm doing this, I'm planning to replace the motor brushes if needed and the capacitors (40+ year old RIFAs are probably bad news), but what I'm unsure about is the choke and resistor? The motor repair kits on eBay contain these parts, but my motor isn't broken, just old. I know nobody can say for certain how it may last, but are these parts particularly common failures, and if they do happen to break, would it cause any other damage? I'm considering this in detail as my cheapest source for the resistor is £15 at the moment, so unless I find it cheaper, it would be a big chunk of my budget. I want to do it properly, but not to spend money on parts that might be perfectly good for another 40 years. Any thoughts about the resistor, or in general, would be much appreciated?

8th Jul 2015, 9:45 am	#2
HG MICKE Pentode Join Date: Jul 2007 Location: London, UK. Posts: 165	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? The 100nf capacitor normally needs replacing, the replacement type is a RIFA PMR209MC RC unit which incorporates a 470R resistor. When this cap fails it blows the choke and the 450R resistor. If the resistor and choke are intact they do not need changing. The carbon brushes would probably need replacing. However the MOST important thing to change and is frequently overlooked are the rubber feet - these allow airflow through the motor assemby and it is overheating that causes most failures. Colin

8th Jul 2015, 12:53 pm	#3
FIXITNOW Octode Join Date: Feb 2007 Location: Ely, Cambridgeshire, UK. Posts: 1,976	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? I have some pdf's that came with the repair kit I fitted, send me your email address if you want them. Vince

8th Jul 2015, 8:31 pm	#4
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? Hi Colin, thank you for explaining about this capacitor/resistor, that's really helped. Do you happen to know if it's in series or parallel however? I couldn't tell from looking at it. As for the feet, I replaced mine a while back as they'd vanished by the time I got the mixer. New feet also stop it walking around the counter while kneading bread dough. Hi Vince, thank you for your offer to send the files, I think that could help a lot as I still have some uncertainties about this mixer. I'll PM you. I managed to take it apart today, and it's a one capacitor motor. Looks like the big grey cylinder capacitor (likely some kind of electrolytic?) is replaced in the kits with a smaller film capacitor. So they weren't fitted with RIFAs originally it seems. I made some other progress too, I fixed the damaged mains lead by cutting off the worn section and rewiring it in to the base of the mixer, and I found a way to revive the original paint. I was cleaning it up and happened to try a can of Servisol De-flux 160 on a stubborn bit of cake splatter, and something rather surprising happen when I wiped the paint. It took off the chalky oxidised surface and suddenly the area I'd cleaned looked new again. Cleaning with detergent had not done this, so it must be something to do with the solvents in the flux cleaner. A little bit of the orange paint had rubbed off on the tissue, but it wasn't very much, and the results are excellent. I just sprayed it on, quickly polished in circles with a tissue, and it looks great. Nice, bright and shiny. As this process is slightly wearing away the paint however, I'd do it once to a kenwood with tired paint to revive it, but not as everyday cleaning. I think a new capacitor and brushes should be all that's needed now.

9th Jul 2015, 8:21 am	#5
HG MICKE Pentode Join Date: Jul 2007 Location: London, UK. Posts: 165	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? The resistor is parallel to the capacitor and is actualy built in the cap package, This capacitor replaces the large metal cased cap. RS stock the cap,If you can not get one I have a couple in stock. Colin

9th Jul 2015, 3:11 pm	#6
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? Hi Colin, thank you for explaining this. It does make sense, I'm just used to newer stuff (about 1980 onwards), so this older style capacitor is an unusual thing for me. Also, thank you for your offer to help with obtaining the capacitor. I have however bought one on eBay yesterday. RS are a fair bit cheaper per capacitor, but only sell them in multiples of five.

11th Jul 2015, 7:57 pm	#7
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? I did the carbon brushes today. The old ones were quite worn. It was very fiddly though, the spring kept curling around and was in danger of being crushed when I tightened the plastic cap. Much more difficult than the brushes I've encountered before in washing machines where the spring is contained inside a metal case. I'm a little concerned the spring isn't in the right place, but I can't see inside once it's assembled. Seems to work well however, and sounds much better now too.

25th Jul 2015, 4:52 pm	#8
Okto1984 Retired Dormant Member Join Date: Dec 2013 Location: Winchester, Hampshire, UK Posts: 288	Re: Refurbishing a Kenwood Chef A701A, and wondering what parts to replace? The mixer is finished now. It got a bit delayed, but the capacitor (RIFA PMR209MC RC) got here in the end, and was simple enough to fit. For anyone who is curious, the carbon brushes aren't so difficult as I thought at first. The secret seems to be to only tighten the plastic caps until they're flush with the case, then the carbon brush and spring puts itself in the right place. I found this by carefully removing them again and looking at how they were placed.