TE-1452G 144 MHz, 400W solid state amplifier repairings & modifications
F5DQK jan 2008, rel 02
1
Réparation d’un ampli VHF TE-Systems 1452G - Ampli reçu en état de marche , mais au contraire des marques concurrentes ne « digérant » pas plus de 25 Win … ATTENTION et PRUDENCE !!!! - A la suite d’une fausse manipe (entrée micro de l’IC-706MKIIg oscillant facilement), les 5 transistors ont rendu l’âme en un rien de temps ! - Au contraire des marques concurrentes (Mirage, RFC, Tokyo Hy Power, etc.. AUCUNE PROTECTION du constructeur n’est prévue en cas de puissance excessive sur l’entrée RF, et de sortie avec TOS prohibitif !! - Platine epoxy commune aux versions 50, 144 et 432 MHz pour Pout>200W Ce PPT illustre les faits suivants: - Subtitution des 5 transistors MRF247 et précautions à prendre - Correction des nombreuses erreurs du schéma de principe (voulues par le constructeur) - Addition d’un fiche PTT Cinch RCA pour être en phase avec la concurrence - « Strap » du transistor driver permettant une Pin max de 60W au lieu de 25W et autorisant ainsi l’emploi de tout TRx moderne. Correspond à la version TE 1454G - Mesures RF Pout fonction de Pin AVEC et SANS driver. Améliorations apportées: - Alimentation +12V pour préampli de mât directement à TRAVERS de l’ampli (fini le sequencer) - Meilleurs circuits de linéarisation (prochaine modification) F5DQK jan 2008, rel 02
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TE-1452G AS RECEIVED FROM UK
- CAUTION: original version with driver doesn’t accept more than 25Win - The IC-706MKIIg mike input is very RF sensitive … and’d QRT the 5 x MRF247 - Absolutely no Rf in overload or Rf out protections !!! F5DQK jan 2008, rel 02
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TE-1452G printboard First note
Mother printboards on TE 0552G, 1452G and 4452G models with Pout>200W are exactly the same (also RA versions) - CAUTION: original version with driver doesn’t accept more than 25Win - Despite of other brands like Tokyo Hy Power, Mirage or RF Concepts, TE-Systems amps have absolutely no Rf in overload or Rf out protections !!! - The IC-706MKIIg mike input is very RF sensitive … and’d QRT the 5 x MRF247
Repairing & modifications steps - Substitution of 4 times MRF247 in both parallel final stages & the MRF247 driver - Bypassing the driver with a coaxial cable allowing now 50 to 60W in = TE-1454G with reverse possibility to use the driver again (only allowing 15W max input) - PTT socket addition (RCA type) - Schematic mistakes corrections - Direct DC feeding compatibility addition for mast preamps (no more sequencer…) - Better biasing circuit (in a nearest future) F5DQK jan 2008, rel 02
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TE-1452G printboard before repairing
F5DQK jan 2008, rel 02
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TE-1452G schematic
Many errors in the initial scheme !
F5DQK jan 2008, rel 02
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TE-1452G printboard after repairing Little teflon coax for driver bypassing
Substitution possible only after desoldering all previous metal clad mica capacitors on base and collector sides F5DQK jan 2008, rel 02
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TE-1452G : driver cap position on base side Normal target (other new amp)
After repairing
10 pF ? Min distance !
F5DQK jan 2008, rel 02
Not optimized
8
TE-1452G : final cap position on base side (1 of 4) Normal target (other new amp)
After repairing
10 pF ? Min distance !
F5DQK jan 2008, rel 02
Not optimized
9
TE-1452G : one final stage after repairing
40 pF ?
1 nF
40 pF ? 10 pF ?
F5DQK jan 2008, rel 02
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TE-1452G : driver changed but « passed through » - more RF input power (>50W instead of maximum 25W) - no more transistors overloading & shutdown - possibility to connect the driver again as formerly (+ collector & base DC inputs)
10 pF ?
40 pF ?
10 pF ?
Little teflon coax for driver bypassing F5DQK jan 2008, rel 02
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TE-1452G : DC bias DRIVER
39Ω, 10W
FINAL 3.3Ω, 0.5W
6.8Ω, 1W 50Ω, 5W
1N9001 Ic=100 mA
F5DQK jan 2008, rel 02
Ic=100 mA per transistor
12
TE-1452G : mods for mast preamp DC feedthru Before - Guardian 1st contact used both for Rfin and DC biasing injection +12V DC in Rx position always present on all collectors & circuitry, except for the DC biasing
Initial bias switching
After - DC biasing is now given by a 2nd separate relay - Guardian relay contacts only used now for RF switching
Mod bias switching allowing now direct masthead preamp feeding with IC-910H or FT-736r rig F5DQK jan 2008, rel 02
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TE-1452G : mods for mast preamp DC feedthru Preamp & TRx relais DC feeding
RFout
GND
RFin DC on Guardian relay in Tx mode DC for preamp F5DQK jan 2008, rel 02
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TE-1452G : mods for mast preamp DC feedthru a/ DC feedthru for masthead preamp direct feeding
After 1 nF
Before RFout 1nF cap (must be taken off & placed between collectors and Relay RF output)
RFin
DC thru
DC bias feeding with RF shoke between RFin and TRx relay input (under VOX_PTT printboard) F5DQK jan 2008, rel 02
Rfin cap (must be taken off)
RFin 15
TE-1452G : mods for mast preamp DC feedthru b/ DC bias separation from RF
Before 2nd DC shoke
After Separated bias relay
GND
(DC bias extracting)
+12V DC bias whith Txing
From +12V switch amp on
50 Ohm RFin line + DC bias PTT line
+12V preamp
Rx +12V Tx 0V
Now DC biasing injection from the rig to the masthead preamp is possible F5DQK jan 2008, rel 02
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TE-1452G: on board GaAs preamp
Amp in
Preamp RFout & +12V
Amp out
Preamp RFin
F5DQK jan 2008, rel 02
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TE-1452G : mods for mast preamp DC feedthru c/ Separate preamp DC feeding
Before
DC shoke (preamp DC bias feeding)
F5DQK jan 2008, rel 02
After
Added DC wire soldered now to relay feeding
DC shoke : 1 pin desoldered
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TE-1452G: on board GaAs preamp Top view
LCout Desolder here Preamp out & +12V DC feeding shoke
7805 Vd Radj
Drain
Autopolar Radj for Vsource =1V
LCin Preamp in + DC shoke
F5DQK jan 2008, rel 02
Gate
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TE-1452G: on board GaAs preamp Bottom view
2 CMS caps for GaAs source RF biasing
Preamp in & DC shoke RF protection with 2 diodes in each transistor
+12V & preamp RF out
F5DQK jan 2008, rel 02
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TE-1452G : mods for mast preamp DC feedthru d/ Gain / Nf measures
Insertion losses
Preamp meas
HP-8970a noise / gain analyser + Ailtech 7615 noise generator F5DQK jan 2008, rel 02
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TE-1452G : VOX scheme Too high resistor, half value is sufficient
F5DQK jan 2008, rel 02
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TE-1452G : VOX & PTT printboard mod Bottom position GND
Initial DC bias feeding coil BEFORE Guardian TRx relay
To TRX Guardian relay
22 kΩ in parallel to the 1st one
With 11 kΩ, the VCE sat in the relay PNP transistor is now 1.5V instead of 4V initially !!
F5DQK jan 2008, rel 02
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TE-1452G : rear of front panel
TE 1406 printboard
F5DQK jan 2008, rel 02
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TE-1452G : adding of PTT cinch socket on rear panel +12V arrival
- The initial remote accessory socket in normal & G versions has no utility - every other brand has a PTT cinch connector F5DQK jan 2008, rel 02
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TE-1452G : printboard connectors pin layout 1 6
2 7
3 8
4 9
5 10
Front panel with switches & LEDs
Rear panel with RF in/out connectors
1 6
On/off connector 1 near front panel
2 7
3 8
4 9
5 10
RF switching connector 2 near rear panel
1
FM/SSB switching
1
Preamp relay
2
DC bias & RF LED
2
Guardian TRx relay
3
+12V after amp on switch before thermal security
3
DC bias output
4
Ground
5
Output LED to 7 on J3
6
Output on J3
7
+12V from 3 conn 1
8
FM/SSB switching from 1 conn 1
9
PTT from 4 conn 1
10
J3 SSB delay pot
4
PTT or remote LED
5
NC
6
Ground
7
Preamp & LED switch
8
+12V after thermal security
9
General +12V incoming
Output F5DQK 10 jan 2008, relJ3 02remote plug
26
TE-1452G : J3 remote plug Cinch PTT connector
+12V arrival J3 connector (not used in RA version)
1 J3 remote plug
7
F5DQK jan 2008, rel 02
6
5
4
3
2
1
FM/SSB
2
PTT
3
+12V, max 1A
4
Preamp
5
PA cntrl gnded
6
Ground
7
LED cntrl gnded
27
TE-1452G: RF power measures
F5DQK jan 2008, rel 02
28
TE-1452G biasing current MRF247 driver 12V
12.5V
13V
13.5V
13.8V
Ib bias (mA)
4.5
8
14
30
33
VBE (V)
0.626
0.625
0.650
0.670
0.675
12V
12.5V
13V
13.5V
13.8V
Ib bias (mA)
6
10
22
48
75
VBE (V)
0.592
0.613
0.635
0.647
0.662
Ic total (A)
0.4
0.7
1.9
2.0
2.2
4 x MRF247 final stages
F5DQK jan 2008, rel 02
29
TE-1452G: Pout versus Pin à 144.400 MHz without driver - Rig IC-706MKIIg, Pin from 3.2 to 50W - Wattmeter Telewave model 44A - Dummy load BIRD Termaline 8135 - 150W - MAAS SPS9600 power supply à 13.8V
=TE 1454G
Pin (W)
12V
12.5V
13V
13.8V
I à 13.8V (A)
3.25
47.5
50
52.5
56
14.4
5
60
65
68
75
16.5
10
110
115
1225.
132.5
21.5
15
140
150
162.5
175
24.4
20
175
182.5
200
212.5
27.3
25
212.5
225
230
250
29.8
30
232.5
250
260
277
31.9
35
262.5
275
282.5
305
34.2
40
277
290
310
330
35.8
45
277
290
310
330
35.8
50
282.5
305
325
350
39.1
F5DQK jan 2008, rel 02
Yield %
30
TE 1452G without driver at 144.35 MHz: Pout/Pin
350
=TE 1454G
300
U=
70
60
8V . 3 1
250
50
Pout(W)
2V 1 U=
200
40
.8V I @ U=13
150
30 Pout (W) à 12V
100
I (Amps)
Pout (W) à 12,5V Pout (W) à 13V Pout (W) à 13,8V I (A) à 13,8V
50
20
10 0
F5DQK jan 2008, rel 02
10
20
Pin (W)
Pin allowed now up to 60W
30
40
50 31
TE-1452G: Pout versus Pin à 144.400 MHz without driver - Rig IC-706MKIIg, Pin from 3.2 to 50W - Wattmeter Telewave model 44A - Dummy load BIRD Termaline 8135 - 150W - MAAS SPS9600 power supply à 13.8V
=TE 1454G
Pin dBm
12V
13.8V
I à 13.8V (A)
35.12
46.77
47.48
14.4
37
47.78
48.75
16.5
40
50.41
51.22
21.5
41.76
51.46
52.43
24.4
43
52.43
53.27
27.3
43.98
53.27
53.98
29.8
44.77
53.66
54.42
31.9
45.44
54.19
54.84
34.2
46
54.42
55.18
35.8
46.53
54.42
55.18
35.8
46.99
54.51
55.44
39.1
F5DQK jan 2008, rel 02
32
TE 1452g without driver à 144 MHz: Pout/Pin P1dBc=55.4 dBm or 348 W
=TE 1454G
56 55 54
Pout (dBm )
53
P1dBc=54.5 dBm or 282 W
8V . 3 1 U=
52 51
12V = U
50 49 48
Pout (dBm) à 12V
47
Pout (dBm) à 13,8V
46 35
F5DQK jan 2008, rel 02
37
39
41Pin (dBm ) 43
45
47
49
33
TE-1452G: Pout versus Pin à 144.400 MHz with driver - Rig FT-847, Pin from 1 to 25W - Wattmeter Telewave model 44A - Dummy load BIRD Termaline 8135 - 150W - MAAS SPS9600 power supply à 13.8V
Pin (W)
12V
12.5V
13V
13.8V I à 13.8V (A)
1 2.5 5 7.5 10 15 20 25 F5DQK jan 2008, rel 02
135 175 212 230 240 260 270 275
155 200 245 262 275 282 300 300
180 230 280 300 310 320 325 332
225 280 330 350 360 370 375 382
Yield %
32.6 36.7 40.5 42 42.8 44.3 45.8 47.8 34
Original manufacturer version !!
TE 1452G with driver at 144,35 MHz: Pout/Pin 400
90
350
80
300
70
Pout (W)
U=13.8V
60
250
U=12V
200
50
150
Pout (W) à 12,5V Pout (W) à 13V Pout (W) à 13,8V I (A) à 13,8V
I (Amps)
I @ U=13.8V
Pout (W) à 12V
100
40
30 0
F5DQK jan 2008, rel 02
5
10
Pin (W)
15
- Max SAFE Pin allowed
