[Repeater-Builder] TAIT T807 power supply repair

[Andreas Papagapiou]

Hi all!

I'm trying to repair a TAIT T807 power supply.
The T4 transformer (115/230V to 18V) was damaged during transport.
I had one custom-made, but without the 115V winding. I installed it and
along with it replaced C37
which looked ... defective.
Now the power supply goes into stand-by mode (red LED comes up), but when I
press the power button
the red led goes off, the green one doesn't come on and there's no voltage
on the output.

Most of the "Initial checks" described in the manual turned out ok. I also
checked most of the diodes
and large resistors which also were ok. The only problem I found was R49
which was open, but that's
used when the mains supply is 115V. Does this also affect operation with
230V?

In the manual under "Common faults" section, the possible cause provided for
this is "defective switching circuitry".
Any ideas for what I should check to identify the problem?

thanks,

Andreas - 5B8AP

[Repeater-Builder] spare parts for TAIT repeater

[Andreas Papagapiou]

Hi all!

I need a replacement transformer for a power supply used in a TAIT T800 UHF
repeater.
The part number on the transformer is *T4079.*

Checking the power supply schematics and the Web, it seems that this is a
mains (115/230V) - 5VA 18V transformer.

Does anyone know where I can get a replacement?

cheers,

Andreas - 5B8AP

[Repeater-Builder] 30A power supply suggestion

[Andreas Papagapiou]

Hi all and Happy New Year!

I'm looking for a power supply for our local repeater.
We are currently using a cheap 20A power supply, but I'm worried it 
may fail under
heavy usage and feed our equipment with higher voltage (it happened 
in the past with a similar
power supply which supplied 35V instead of 13.8)

What I want is a reliable 13,8V, 30A power supply that can provide at 
least 15A at 100% duty cycle.
It also needs to be light (i.e. switching, not transformer type), so 
that I won't have to pay a fortune to have it shipped here.
Any suggestions on models or online shops I can order from?

cheers,

Andreas - 5B8AP

[Repeater-Builder] info on Kenwood TKR-720

[Andreas Papagapiou]

Hi all,

Can anyone provide some information on the Kenwood TKR-720 repeater?
I checked eham.net but did not find any reviews. What I'd like to know:
- Does it have good sensitivity and clear audio?
- In general, is it a good repeater?
- Can it be easily tuned down to amateur frequencies?
- How can it be programmed? Do we need special software?

How would you compare it with the TAIT T800 units (if you are 
familiar with both)?

73,

Andreas - 5B8AP

[Repeater-Builder] Re: Tait 800 - EPROMS, Manuals, Software

[Andreas Papagapiou]

Hi Ed and group!

I have the manuals for T838 PA, T837 Exciter and T835 RX scanned in PDF form.
I uploaded them on Rapidshare.

You can download them from 
http://rapidshare.com/files/141353699/TAIT_T800_Manuals.zip.html

The file size is around 69MB.

Hope they are the ones you are looking for.

73,

Andreas - 5B8AP


> If you want I can scan my manuals for the series 1 Taits for 2mtrs.
> You will just have to give me some time, have to take the wife to a
> Russian weekend this weekend.
>
> Regards
>
> Kevin, ZL1KFM.
Kevin,
That would be great.
Thanks,
Ed Yoho
W6YJ

[Repeater-Builder] custom duplexer cables

[Andreas Papagapiou]

Does anyone know of a company that manufactures good quality
custom duplexer cables (for specific frequency and with specific connectors)?

We need a set of cables to use with a new Sinclair duplexer and a 2m repeater,
N-type connectors on the one site, PLs on the other.

thanks,

Andreas - 5B8AP

[Repeater-Builder] ID-O-Matic and T800 unit

[Andreas Papagapiou]

Hi all,

Has anyone interfaced an ID-O-Matic CW IDer to a TAIT T800 repeater?
I have the kit ready, but I need instructions "for dummies" on how to 
connect it :-)
If possible, I'd like to make it "polite" i.e. transmit the ID every 
10 minutes or when
the repeater is activated after some time of inactivity, but not 
while the repeater is
being used.

73,

Andreas - 5B8AP


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[Repeater-Builder] Re: VHF Engineering Tx Help Needed

[Andreas Papagapiou]

Hello Doug,

I had a similar problem with a VHF Engineering Transmitter-PA.
Incoming signals would key the repeater but there was no RF output.

First you need to find out if the fault is in the TX or the PA. The 
output of the TX
alone should be 1-1.5W. If that's ok, then you should focus on 
finding a problem in the PA.
If I remember correctly the way I tested it was by connecting a power 
meter to the
output of the TX to see if the output power was ok. I got 1-1.5W as 
expected so the
next step was connect a 1W input signal taken from a handheld radio 
to the input of the PA.

The output was almost zero.
In my case the fault was with the final transistor (2N 6081). After 
replacing it the output was
around 3-4W but after following the tuning procedure described in the 
manual it went up to 15W.
You might want to do this first, just in case the low output is due 
to a misalignment problem.


Now if the problem is with the TX module... I would check if the 
transistors are ok...


You can get all the manuals from the Repeater builder website as pointed out
by Eric.

Hope this helps.

73,

Andreas - 5B8AP


Doug,
The Repeater-Builder site has good info on VHF Engineering equipment. Here
is the PA manual:

73, Eric Lemmon WB6FLY

-Original Message-
From: 
Repeater-Builder@yahoogroups.com

[mailto:[EMAIL PROTECTED] On Behalf Of dadavies3
Sent: Wednesday, November 07, 2007 2:24 PM
To: 
Repeater-Builder@yahoogroups.com

Subject: [Repeater-Builder] VHF Engineering Tx Help Needed
I have an old VHF Engineering 144 MHz. repeater transmitter that has
very low output. I would like to find someone that has experience
with one of these that can help me trouble shoot it. Any help is
appreciated.
Doug VE7DRF


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7:29 ìì

[Repeater-Builder] VHF Engineering PA-144 repair

[Andreas Papagapiou]

Hello everyone,

We have an old repeater made of "VHF Engineering" kits.
The repeater suddently became silent. It seems that there's a problem 
with the PA module
(PA-144). I used a handheld radio to provide 1W input to the PA, but 
there's no output.

Did anyone have a similar problem? Any ideas of what could be wrong?
I've never tried to repair a PA again, so I need a place to start... :-)

cheers,

Andreas - 5B8AP


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