CRT SS 9900 doorstops

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Dragonfly
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CRT SS 9900 doorstops

Post by Dragonfly »

Picked up 2 ss 9900 locale for £20 but both in a bad way , This one lights up and recieves but no output , Inside one finale seems to be missing and the other 3 appear to be Fairchild 13n10L , on the other side is a burnt track . Solder on the power cable so i think its had a fan or something butchered in .
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Last edited by Dragonfly on 18 Jul 2016, 17:30, edited 1 time in total.
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Re: CRT SS 9900 doorstops

Post by Dragonfly »

Burned track on the solder side .
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Re: CRT SS 9900 doorstops

Post by Admiral »

At £10 each even if they cost £40-£50 each to fix you're still quids in.
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Re: CRT SS 9900 doorstops

Post by Dragonfly »

The second 9900 has had the TIP36C butchered out and has the same burnt track .
Just ordered 25 finals and 5 TIP36C from RS to give them the once over , Fingers crossed .
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Re: CRT SS 9900 doorstops

Post by 163TM847 »

I would have given £10 each for them with output faults too as output fault on a mosfet radio is usually an easy fix, But fixing someone else's bodged attempt is annoying.

Little advice
Make sure the gate voltage on the mosfets does not exceed 3.55v [SSB TX no audio] before installing the Mosfets, Then check it again after installing them.

Looks like one or more have gone dead short before causing the tracks to fry.
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Re: CRT SS 9900 doorstops

Post by Dragonfly »

Cheers Nick , Seems these do 30w AM and 50w on fm , with such a small case and small heat sink No wonder the finals dont last long .
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Re: CRT SS 9900 doorstops

Post by astradyne »

It amazes me how radio's that really aren't that old get into such a state. Some true idiots out there.

I've had my 9900 for 18 months now and not had a single issue. I expect someone's cranked up the FM power as high as it will go and played jungle music till the outputs went.

When used sensibly and correctly there's no reason why these radio's shouldn't go on working.
Never, ever, ever....bloody anything ever!

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Re: CRT SS 9900 doorstops

Post by Dragonfly »

Took the old finals out of no 1 radio and checked the gate voltages on the fets , 2 were 3.49v other 2 were 3.76v and 4.6v so ive trimed the lot at 3.49v ,would 3.49 be ok to install and try the new finals .
The radio has TX and audio from FM USB LSB but no TX or audio heard from AM to a nearby radio from the pre driver .
Radio wont move channel when the frequency is on the screen but changes fine when switched to channel numbers , is this normal . Do these radios use a 15 amp inline fuse , ive put a 10a in for now while ive tested it .
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Re: CRT SS 9900 doorstops

Post by dt307 »

i had one that froze up on vfo frequency mode did a factory reset and it came right
also had to do a mod to the mic on 3 of them i got the mod direct from a tech at crt because rf can get into the mic and cause it to jump a channel when de keyed normally when you first turn them on
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Re: CRT SS 9900 doorstops

Post by Bandolier »

Mod to microphone
Hi dt307 hope you see this post been trying to pm you but I don't think they were sent, you talk of a mod for the mic to stop rf getting in I am
having the same problem on my crt ss 9900 could you give me details of the mod. Thank you.
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Re: CRT SS 9900 doorstops

Post by cb4ever104 »

Bandolier wrote: 08 Dec 2018, 12:23 Mod to microphone
Hi dt307 hope you see this post been trying to pm you but I don't think they were sent, you talk of a mod for the mic to stop rf getting in I am
having the same problem on my crt ss 9900 could you give me details of the mod. Thank you.
I've sent Chris a PM for you , as I don't think you have enough posts to do so . Hopefully he'll get back to you soon .

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Re: CRT SS 9900 doorstops

Post by dt307 »

this was sent to me via a tech in crt
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Re: CRT SS 9900 doorstops

Post by dt307 »

sorry got lot on guys didnt see the post
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Re: CRT SS 9900 doorstops

Post by Bandolier »

Hi Chris
Thank you for the info, I emailed crt a few times they kept saying they would send me the info but never did!.

Steve,
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