Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Jul Wed 15, 2020 11:59 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 85 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Thu 05, 2019 9:46 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Well I have it superglued for now just trying to figure out the dial cord layout until the new manual gets here currently stuck in new jersey


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Sun 15, 2019 12:08 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
just got the new multi can capacitor from Heyseed Hamfest and now I see why people recommend him the quality is great and it fits like a glove in the original can's spot even the sections line up where the old ones did


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Tue 17, 2019 3:23 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Okay now that I have the schematic I can see 3 caps that have been changed before with incorrect values the phono preamp plate cap has been replaced with a 20 mfd 300 v in place of a 40 mfd 300 v and the cathode bypass cap of 2 of the 6bm8's has been replaced with a 6 mfd 30v cap when it should be a 10 mfd 10 v


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Tue 17, 2019 10:13 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Not sure if I should go ahead and replace or try it as is as the solder joints on the caps that do not match the schematic look the same as the rest of the factory joints


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Thu 19, 2019 1:23 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
either way here is a scanned copy of the manual for anyone who needs it still undecided on the out of spec caps might see how it sounds with them in since they appear fine and factory then replace with whats in the schematic I think I might have a mid production run revision here


Attachments:
File comment: roland/rotel/matel fax-200c manual
Roland_manual[1].pdf [4.55 MiB]
Downloaded 35 times
Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Sat 21, 2019 10:47 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Oops just tried turning on after getting the new power supply caps installed and realized the hard way that I had the filament wire to the fm front end hooked up backwards ow I have to wait until after the holidays to get some new 6bm8's as I broke one in my panic to find the source of the smoke which was the filament wire under the chassis leading to the circuit board where the fm front end tube gets its power from oops I dislike making mistakes like this even if I was planning to replace all tubes anyway


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Sun 22, 2019 10:47 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Well got the messed up wire fixed and the 3 power filter caps well 5 if you count the multi-capacitor can capacitors separate put all tubes minus the busted one in no peep out of left speaker if 2 of the good tubes are in it which before I got terrible garbage out of that channel not sure of cause for this but now on the right channel if 2 good tubes are in it sounds great but the middle 2 output tubes still red plate not sure if a replacement tube set will fix this or if I should replace the rest of the electrolytic capacitors especially the 3 that are out of spec according to the schematic


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Dec Mon 23, 2019 3:32 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Never mind figured out what was wrong with lift channel the cathode bypass capacitor had shorted to pin 1 of it's tube effectively killing the signal.
still red plateing on both channels though will replace output tubes and rest of electrolytic capacitors to try and fix


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sat 11, 2020 2:24 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Well all electrolytic caps and the 2 over value cathode bypass resistors are replaced still red plating also replaced the 500 picofarad cap in the am section where one sides wire had disappeared am still not working only think I can think of now is to replace all tubes if that doesn't work go through all resistors with a ohm meter and the paper in oil caps with a voltmeter on dc and see if any of them are leaking


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sat 25, 2020 11:05 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
even after replacing all the over value resistors and getting new tubes the right channel still red plates guess I will have to order replacements for the pio capacitors for it


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 12:10 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
found the issue the paper in oil caps on the middle tubes are leaking around 50 volts to the control grids


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 2:33 am 
Member

Joined: Aug Wed 24, 2011 4:35 am
Posts: 4970
Location: Sunnyvale CA
SpaceFerret42 wrote:
found the issue the paper in oil caps on the middle tubes are leaking around 50 volts to the control grids


"Paper in oil" capacitors of any type are not reliable and any of them (either old, NOS, or from Russian Army surplus) should be discarded and replaced with conventional film caps.

BTW, the "oil" is likely to be PCBs, which are nominally toxic, although unless you put it in a syringe and inject it, is probably not that dangerous. But don't burn them.

Brett


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 3:03 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Interesting i always heard they was reliable my bad


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 3:05 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Then perhaps i will go through and replace them all with lemon drop capacitors then


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 5:00 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11665
Location: Fernandina Beach, FL
The audio crowd seems to be mesmerized by the Soviet "Paper-In-Oil" capacitors. I have always used and had good luck with either Orange Drops or yellow axial capacitors. Frankly, I would not be putting paper back into an amplifier that I was restoring.

_________________
Don


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 5:57 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
I always had the understanding that all capacitors eventually wear out. So I always replace wax or old electrolytics with new but thought I heard somewhere that pio caps where more relible for longer then wax guess not error will be fixed
geuss only ceramics are reliable


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 8:51 pm 
Member

Joined: Aug Wed 24, 2011 4:35 am
Posts: 4970
Location: Sunnyvale CA
SpaceFerret42 wrote:
I always had the understanding that all capacitors eventually wear out. So I always replace wax or old electrolytics with new but thought I heard somewhere that pio caps where more relible for longer then wax guess not error will be fixed
geuss only ceramics are reliable


"Paper in oil" are just like bumblebee caps without the hard plastic case. Certain areas of the audio world consider them to have better tone, or are less gritty, or something equivalently nonsensical. The only place they are commonly available is from Soviet Army Surplus.

Use poly film capacitors. I don't know what a "lemon drop" capacitor might be, but the yellow film caps sole by Sal Brisindi are just fine. I would match them for value side-to-side, but otherwise, the are nice and stable. Depending on how they are mounted, you may want radial leads instead of axial. Get them from manufacturers you would recognize, DO NOT get "audiophile" capacitors, DO NOT get "Wonder Caps", just plain old industrial-quality are what you want.

I would not use ceramic disc capacitors unless that was what was there in the first place, they tend to be microphonic. You won't be able to find them in the capacity and rating you need for most of the places, in any case.

Brett


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Sun 26, 2020 9:00 pm 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
Lemon drops are what i heard the yellow film caps called often


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Mon 27, 2020 12:04 am 
Member

Joined: Aug Wed 24, 2011 4:35 am
Posts: 4970
Location: Sunnyvale CA
SpaceFerret42 wrote:
Lemon drops are what i heard the yellow film caps called often


I would choose whatever fits the existing circuit the best. I presume that this is PWB-based rather than point-to-point wiring, and usually, PWBs use radial-lead capacitors. Whatever it needs. As above, avoid "audiophile" components.

Brett


Top
 Profile  
 
 Post subject: Re: Roland/Martel (Rotel) FAX-200C
PostPosted: Jan Mon 27, 2020 1:06 am 
Member

Joined: Nov Thu 07, 2019 11:11 pm
Posts: 95
This particular unit is a mix of pcb and point to point wiring but all caps in it from factory are either axial pio caps or radial ceramic disc caps with a few mica thrown in


Top
 Profile  
 
Post New Topic Post Reply  [ 85 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 4 guests



Search for:
Jump to:  


































-->


Privacy Policy :: Powered by phpBB