FT-818 Review and Disassemble

| agosto 28, 2018

FT-818 Review and Disassemble

FT-817 comparison with FT-818

FT-818  At first glance I do not understand the difference with FT-817

With manufacturer’s flyer Power up from 5 W to 6 W, High precision 0.5 ppm TCXO standard equipment 1900 mA/h nickel hydrogen battery standard equipment

First check basic performance easily

Confirm transmission output and frequency in CW mode

output

  • 1.8 M: 6.08 W
    3.5 M: 6.09 W
    7 M: 6.12 W
    14 M: 5.89 W
    28 M: 6.18 W
    50 M: 5.83 W
    144 M: 5.86 W
    430 M: 5.62 W

It can be said that it is sufficient as it is rated

frequency
430.000 MHz: 429.999989 MHz – – – 0.03 ppm

Regarding reception, I checked with CW, FM in each band but it was as per the rating

Okay.

Disassembly

Main board:

FT-818 Review and Disassemble

The left is FT-817
The right is FT-818

At first glance … It looks like it has not changed much

Changes to the reception circuit of wide FM

FT-818 Review and Disassemble

The left part of red circle is FT-817
The right is FT-818

The UHF front end has also changed

FT-818 Review and Disassemble - FT-817 comparison with FT-818

The red circle where the left is FT – 817
The right is FT-818

PA substrate

FT-818 Review and Disassemble - FT-817 comparison with FT-818


The left is FT-817
The right is FT-818

Looking at Pat is about the relay changed from Omron to Takamizawa

Looking closely, the parts change is contained little by little, but they are almost similar

FT-818 Review and Disassemble - FT-817 comparison with FT-818

Around the final

The left is FT-817
The right is FT-818

FT-818 Review and Disassemble - FT-817 comparison with FT-818

TCXO is newly established

Above: FT-817
Medium: TCXO-9 (FT-817 option ± 0.5 ppm)
Bottom: FT-818 (TCXO ± 0.5 ppm)

Here, the trace which FT-818 seems to be a minor change of not only the successor model of 817 but …

It seems that Yaesu has assigned a 7-digit part number to the parts to be used. And in the case of a small change, instead of giving a new part number,
Change from 0 → A → B → C …

FT-818 Review and Disassemble - FT-817 comparison with FT-818

Looking at the main board here

Left: 005180 G: FT – 817 lot 75 or later Right: 005180 K: FT – 818

The panel board (front)

The same 006170F as FT – 817 is used

By the way, as a big difference PLL IC from FQ7925 (Yaesu exclusive item)
It would have been replaced by AD 4116 (Analéva)

In addition, the small signal high frequency Tr is replaced with 2SC 5374 → 55 GN 01 FA …

After all for the last 20 years I replaced the parts that became a discon, and it became a level that greatly influences the transmitter system diagram so that it is not the main point that I released it with a new part number?

Since I do not know what to say if I keep it, output up (some overseas have raised the adjustment value of 817 to about 10 W)
Changed ni-mh by installing tcxo as standard

I wonder if I thought that I could devastate the world

FT-818 Modification

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